Lochinvar LTM-199X3-N 100 XCalibur® Standard Condensing User Manual

Service Handbook

THIS SERVICE HANDBOOK IS FOR USE BY QUALIFIED SERVICE PROFESSIONALS ONLY.

Standard Condensing

Residenal Gas

Tankless Water Heater

Residenal On-Demand Gas Tankless Water Heater

(X3® TECHNOLOGY available on some models)

2000848848_REV.AJuly 2025

MODELS:

TM-160M-N, TM-180M-N, TM-199M-N

TM-160X3-N, TM-180X3-N, TM-199X3-N

NATURAL GAS ONLY

(M MODELS AVAILABLE IN US ONLY)

2 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

BASICS

TABLE OF CONTENTS

BASICS ........................................................................ 2

Typical Installaon (X3® Model Shown).............................. 3

IMPORTANT SAFETY INFORMATION ............................ 4

RISKS DURING INSTALLATION AND MAINTENANCE ............ 5

RISKS DURING OPERATION ................................................. 5

Tools Required for Servicing Tankless Gas Water Heater

Models ................................................................................ 6

COMPONENT TESTING AND DIAGNOSIS ..................... 7

Hi-Limit Switch (Manual) .................................................... 7

Cascade System .................................................................. 8

OPERATION ...............................................................12

Display Overview .............................................................. 12

Temperature Sengs........................................................ 13

Conguraon Mode (C Mode) .......................................... 14

Unit Conversion Mode ...................................................... 16

Informaon Mode (P Mode) ............................................ 17

MAINTENANCE ..........................................................18

Descaling .......................................................................... 18

Unit Draining & Power Outage (Freeze Protecon) .......... 20

Discharge Condensate ...................................................... 20

Inlet Water Filter .............................................................. 20

X3® & Bypass Cartridge .................................................... 21

TROUBLESHOOTING ..................................................22

General Troubleshoong .................................................. 22

Error Codes ....................................................................... 24

Fault Analysis of Error Codes ............................................ 25

SERVICE (ELECTRONIC & WIRING COMPONENTS) ......32

User Interface Module & Wire Harness ............................ 32

Hi-Limit Switch (Manual Reset) ........................................ 34

Freeze Protecon Thermostat .......................................... 35

Heater Block Upper Wiring Assembly............................... 36

Heater Block Lower Wiring Assembly ............................... 38

Main Wiring Harness Assembly ........................................ 42

Freeze Protecon & Power Wire Harness Assembly ........ 46

Printed Circuit Board ........................................................ 48

Ignitor Assembly ............................................................... 50

Flame Sensor Wire............................................................ 51

Exhaust and Water Inlet Thermistor ................................. 52

Heat Exchanger and Water Outlet Thermistor ................. 55

SERVICE (COMBUSTION COMPONENTS) ....................58

Gas Inlet Connector .......................................................... 58

Gas Valve .......................................................................... 60

Fan Assembly .................................................................... 64

Gas Manifold .................................................................... 68

Ignitor Rod & Flame Sensor Rod Assembly ....................... 71

Burner Assembly .............................................................. 73

Primary & Secondary Heat Exchangers (HEX), OHCF Wire 76

SERVICE (WETTED COMPONENTS) .............................86

Water Inlet Assembly ....................................................... 86

Flow Control Valve ............................................................ 88

Cartridge Manifold ........................................................... 90

Bypass Valve ..................................................................... 92

Water Outlet Assembly .................................................... 94

Water Tubing .................................................................... 96

Condensate Trap ............................................................. 100

Heat Exchanger (HEX) Drain ........................................... 102

Inlet Water Filter ............................................................ 104

SERVICE (FLUE & AIR INTAKE COMPONENTS) ...........105

Emission Port Cap ........................................................... 105

Flue & Air Intake O-Ring ................................................. 106

Flue & Air Intake Clamp .................................................. 108

SERVICE (MASTER KITS) ...........................................109

Gasket Master Kit ........................................................... 109

Fastener Master Kit ........................................................ 112

O-Ring Master Kit ........................................................... 114

COMPONENTS .........................................................116

Internal Component View (A) ......................................... 116

Internal Component View (B) ......................................... 117

External Component View .............................................. 118

Internal / External Component List ................................ 119

DIAGRAMS ..............................................................120

Electrical Wiring Diagram ............................................... 120

Thermistor Resistance Vs Temperature Charts ............... 121

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 3

TYPICAL INSTALLATION (X3® MODEL SHOWN)

BASICS

Water

Shut-off Valve

Expansion

Tank

Gas

Line

CWS

HWS

Gas

Shut-off Valve

Pressure Relief Valve

(Drain Line not

shown for clarity)

Drip Leg

Flue Gas ExhaustAir Intake

Condensate Drain

(Drain Line not

shown for clarity)

(Hot Water Supply)

(Cold Water Supply)

Water

Shut-off

Valve

4 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SAFETY

IMPORTANT SAFETY INFORMATION

Read and follow all safety messages and instrucons in this

manual.

This is the safety alert symbol. It is used to alert you to

potenal physical injury hazards. Obey all safety messages

that follow this symbol to avoid possible property damage,

serious injury or death. Do not remove any permanent

instrucons, labels, or the data plate from either the outside

of the water heater or on the inside of the access panels. Keep this manual

near the water heater.

DANGER indicates a hazardous

situaon that, if not avoided, will

result in death or serious injury.

WARNING indicates a hazardous

situaon that, if not avoided, could

result in death or serious injury.

CAUTION indicates a hazardous

situaon that, if not avoided, could

result in minor or moderate injury.

NOTICE indicates pracces not

related to physical injury.

DANGER

WARNING

CAUTION

NOTICE

WARNING! If the informaon in these instrucons is not followed

exactly, a re or explosion may result causing property damage, personal

injury or death. Do not store or use gasoline or other ammable vapors and

liquids in the vicinity of this or any other appliance.

An odorant is added by the gas supplier to the gas used by this water heater.

This odorant may fade over an extended period of me. Do not depend upon

this odorant as an indicaon of leaking gas. We recommend installing a fuel

gas and carbon monoxide detector.

This product is cered to comply with a maximum weighted average of

0.25% lead content as required in some areas.

*Operate the Pressure Relief Valve

annually and inspect Pressure Relief

Valve every 2-4 years (see the label

on the Pressure Relief Valve for

maintenance schedule). If no label

is attached to the Pressure Relief

Valve, follow the instructions in the

Maintenance section of this manual.

See the Regular Maintenance section

for more information about maintaining

this water heater.

Important informaon to

keep

Fill out this secon and keep this manual

in the pocket of the water heater for

reference.

Date Purchased:

Model Number:

Serial number:

Maintenance performed:* Date:

To reduce the risk of property

damage, serious injury or death, read

and follow the precauons below,

all labels on the water heater, and

the safety messages and instrucons

throughout this manual.

RISKS DURING

INSTALLATION AND

MAINTENANCE

Liing Risk

WARNING! The

water heater is

heavy. Follow these

precauons to reduce the risk of

property damage, injuries from liing

or impact injuries from dropping the

water heater.

• Use at least two people to li the

water heater.

• Be sure you both have a good grip

before liing.

• Use an appliance dolly or hand truck

to move the water heater.

Explosion Risk

WARNING! This water

heater is designed for

Natural Gas operaon only. Refer

to the water heater’s rang plate.

Failure to follow these instrucons

can result in serious injury or death

from explosion, re or carbon

monoxide poisoning.

• DO NOT connect this Natural Gas

water heater to an L.P. gas supply.

• Use a new gas supply line approved

for Natural Gas that meets local and

state/provincial codes.

• Install a full port shut-o valve on

the gas supply line.

• Maintain the Pressure Relief Valve

properly. Follow the maintenance

instrucons provided by the manu-

facturer of the Pressure Relief Valve

(label aached to Pressure Relief

Valve). If no label is aached to the

Pressure Relief Valve, follow the

instrucons in the Pressure Relief

Valve Maintenance secon of this

manual. An explosion could occur if

the Pressure Relief Valve or dis-

charge pipe is blocked. Do not cap

or plug the Pressure Relief Valve or

discharge pipe.

Gas Pressure

WARNING! The Natural Gas

supply pressure must not exceed the

maximum supply pressure as stated

on the water heater’s rang plate.

Have a qualied person (licensed

plumber, gas company personnel,

or authorized service technician)

check for proper gas pressure. Gas

pressures exceeding the maximum

supply pressure as stated on the

water heater’s rang plate can

result in serious injury or death from

explosion or re.

RISKS DURING

OPERATION

Scalding Risk

This water heater

can make water hot

enough to cause

severe burns instantly, resulng in

severe injury or death.

• Feel water before bathing or show-

ering.

• To reduce the risk of scalding, install

Thermostac Mixing Valves (tem-

perature liming valves) at each

point-of-use. These valves automa-

cally mix hot and cold water to limit

the temperature at the tap. Mixing

valves are available at your local

plumbing supplier. Follow the manu-

facturer’s instrucons for installaon

and adjustment of the valves.

• Water temperatures over 125°F

(52°C) can cause severe burns

instantly or death from scalding. The

water temperature is set at 120°F

(49°C) from the factory to minimize

any scalding risk. Before bathing or

showering, always check the water

temperature. Higher temperatures

increase the risk of scalding, but even

at 120°F, hot water can scald. If you

choose a higher temperature seng,

Thermostac Mixing Valves located

at each point-of-use are parcularly

important to help avoid scalding.

Table 1: Scalding Table

Temperature

Time to Produce a

Serious Burn

120°F (49°C) More than 5 minutes

125°F (52°C) 1½ to 2 minutes

130°F (54°C) About 30 seconds

135°F (57°C) About 10 seconds

140°F (60°C) Less than 5 seconds

145°F (63°C) Less than 3 seconds

150°F (66°C) About 1½ seconds

155°F (68°C) About 1 second

For more informaon about changing

the factory temperature seng, refer

to the “Temperature Sengs” secon

in this manual.

• Water temperature will be hoer if

someone adjusted the set tempera-

ture to a higher seng.

• Should overheang occur or the

burner fail to shut o, turn o the

manual gas supply valve to the

water heater and call a qualied

person.

To reduce the risk of unusually hot

water reaching the xtures in the

house, install Thermostac Mixing

Valves at each point-of-use.

If anyone in your home is at parcular

risk of scalding (for example, the

elderly, children, or people with

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 5

IMPORTANT SAFETY INFORMATION

SAFETY

6 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

disabilies) or if there is a local code

or state/provincial law requiring a

certain water temperature at the

hot water tap, these precauons are

parcularly important.

According to a naonal standard

American Society of Sanitary

Engineering (ASSE 1070) and most

local plumbing codes, the water

heater’s thermostat should not be

used as the sole means to regulate

water temperature and avoid scalds.

Water Contaminaon Risk

Do not use chemicals that could

contaminate the potable water

supply. Do not use piping that has

been treated with chromates, boiler

seal, or other chemicals. Suitable for

potable water heang only.

Fire Risk

To reduce the risk of

a re that could result

in property damage, or serious injury

or death:

• Do not store things that can burn

easily such as paper or clothes next

to the water heater.

• Do not store or use gasoline or other

ammable substances in the vicinity

of this or any other appliance.

• Do not use this appliance if any part

has been in contact with or been im-

mersed in water. Immediately call a

qualied installer or service agency

to replace a ooded water heater.

Do not aempt to repair the unit. It

must be replaced.

Explosion Risk

High pressures in the

water heater can cause

an explosion resulng in property

damage, serious injury or death. A

Pressure Relief Valve is required to

be installed on the water heater.

A Pressure Relief Valve is supplied

with X3® models and shall be eld

supplied for M models. Addional

pressure protecve equipment may

be required by local codes.

A naonally recognized tesng

laboratory maintains public inspecon

of the valve producon process

and ceres that it meets the

requirements for Relief Valves for Hot

Water Supply Systems, ANSI Z21.22.

The Pressure Relief Valve’s relief

pressure must not exceed the working

pressure rang of the water heater as

stated on the rang plate.

Carbon Monoxide Risk

WARNING! This

water heater

operates by burning

gas. Carbon

monoxide is a

colorless, odorless,

gas that is a by-product of burning of

fuels such as coal, wood, charcoal,

oil, kerosene, propane, and natural

gas. Breathing excessive and

abnormal amounts of carbon

monoxide can cause carbon

monoxide poisoning, resulng in

serious injury or death. This water

heater must be supplied with

adequate combuson air and must

be properly vented to the outdoors.

Have a qualied person (licensed

plumber, authorized gas company

personnel, or authorized service

technician) install the venng system

using these installaon instrucons.

Install a fuel gas and carbon

monoxide detector in the living areas

of your home.

Failure to follow these instrucons

can result in serious injury or death

from carbon monoxide poisoning.

Tools Required for

Servicing Tankless Gas

Water Heater Models

• Safety gloves

• Non-contact circuit tester

• Common hand tools (screwdrivers,

pliers, wire cuers, wrenches, etc.)

• 12" Magnezed Phillips screwdriver

• Plasc scraper

• Digital mulmeter (with alligator

leads and connuity tester)

• Clamp style amp meter

• Water pressure gauge

• Garden hose (draining tank)

• Bucket

• Thermometer (2x)

• Pipe wrench for water and gas

connecons

• Pipe joint compound or thread

sealant tape

• Masking tape and a permanent

marker to mark wires

• Cable es (various sizes)

• Mini Pick or Hook

• Installaon Instrucon/Use and Care

Guide

IMPORTANT SAFETY INFORMATION

SAFETY

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 7

COMPONENT TESTING AND DIAGNOSIS

COMPONENT DATA

Hi-Limit Switch

(Manual)

The Hi-Limit switch (manual) can be

manually reset by depressing the

buon in the center of the switch.

This switch acvates at 217°F (103°C).

It will ash an E002 error code.

Screw

Wire

Lead

Wire

Lead

Figure 1 - Hi-Limit Switch (Manual)

Cascade System

Installaon and Conguraon

The Cascade System allows up to 12

heaters of the same input model to be

linked electronically for various ow

rate demands.

The Installaon Instrucons and

Use & Care Guide provides the

correct procedures for installing and

conguring the Cascade System.

One heater MUST be set as the Parent

water heater. The Parent water heater

will instruct the Child water heaters

in the Cascade System to acvate and

deacvate as necessary.

Mode C13 sets the Parent water

heater by idenfying the number of

Child water heaters in the Cascade

System.

Mode C14 idenes the water

heater number in the system. The

Parent heater will always have a

value of 1. The Child water heaters

will have a value of 2 up to 12. See

Figure 2 below for an example of a

typical Cascade System and how it is

congured.

Priority Order Determinaon

The heaters will rotate the Priority

water heater (rst to acvate) on

a weekly basis. The Priority water

heater will be set based on the water

heater with the least combuson

me. The second water heater will

be set based on the water heater

with the second least combuson

me, and so on for the remaining

water heaters in the Cascade System.

The combuson me for each water

heater can be viewed in mode

P20. See Table 15 on page 17 for

informaon on accessing P mode.

Acvaon and Deacvaon

Logic

Water heaters in the Cascade System

will acvate and deacvate based

on the water temperature rise of

the Priority water heater. Tables 2-5

(pages 10 & 11) list the acvaon

and deacvaon of the model

based on the Priority water heater’s

temperature rise (ΔT):

ΔT = T

set

- T

set

= Set Temperature

= Inlet Temperature

The tables show the system ow

rate when the next water heater will

acvate and likewise deacvate.

8 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

COMPONENT DATA

COMPONENT TESTING AND DIAGNOSIS

PARENT

UNIT A

HWS

GAS

CHILD

UNIT B

CHILD

UNIT C

CWS

BUILDING

RETURN

CHILD

UNIT D

C13 = 3

C14 = 1

C13 = 0

C14 = 2

C13 = 0

C14 = 3

C13 = 0

C14 = 4

C Mode Parent

Unit A

Child

Unit B

Child

Unit C

Child

Unit D

C13 3 0 0 0

C14 1 2 3 4

Seng

Figure 2 - Cascade System Installaon & Conguraon

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 9

COMPONENT DATA

COMPONENT TESTING AND DIAGNOSIS

Tesng a Cascade System

Verify the system is installed as shown

in the water heater’s Installaon

Instrucon Use and Care & Guide.

The water piping must be installed in

a “Reverse-Return” format to promote

equal “path of resistance” through

each water heater in the Cascade

System.

IMPORTANT: Unequal paths of

resistance will cause some water

heaters to operate more frequently

than other units in the Cascade

System and can lead to uctuaon of

outlet water temperatures.

If the issue is an error code, check for

the following:

See "Cascade System Example" on

page 24 for more informaon

on how error codes will display in a

Cascade System.

1. Verify the heaters are set properly

in the C13 & C14 modes.

• Press and hold the “UP”

buon and the “SETTING”

buon for 5 seconds to access

C Mode.

• Press the “UP” buon or the

“DOWN” buon to search for

the desired C Code.

• Press and hold the “UP” but-

ton and the “SETTING” buon

for 5 seconds to return the

display to normal operaon.

2. Test the water heater(s) with an

error code as an individual unit,

removing it from the Cascade Sys-

tem. Do this by changing mode

C14 to 0.

NOTICE: Record the original value

of C14 before changing to 0. This

value will need to be reentered

once the error code has been

resolved.

• Press and hold the “UP”

buon and the “SETTING”

buon for 5 seconds to access

C Mode.

• Press the “UP” buon or the

“DOWN” buon to search for

the desired C Code.

• If applicable, press the

“SETTING” buon to adjust

the value of the C Code using

the “UP” and “DOWN” but-

tons. The value will ash.

• Press the “SETTING” buon

again to conrm the new

value selected is correct.

• Press and hold the “UP” but-

ton and the “SETTING” buon

for 5 seconds to return the

display to normal operaon.

NOTICE: If the problem water

heater is the Parent unit, you will

need to set the next water heater

in line as the new Parent unit.

3. Disconnect the cascade wiring

from the water heater. Cycle the

power of the heater o, then on.

DO NOT use the ON/OFF buon

on the user interface module.

• Before proceeding, determine

if isolaon valves are installed.

If so, close the outlet valve

and hook up a hose to the iso-

laon valve port. Run the hose

to a drain or outside in order

to operate the water heater as

an individual water heater.

• If isolaon valves are not

installed, you will have to test

the water heater while the

overall system is not in use.

4. Refer to the "Fault Analysis of Er-

ror Codes" secon on page 25

for error code informaon.

5. Once the error code is resolved,

reaach the cascade wire to the

water heater’s PCB. Return to

mode C14 and set the display to

the previous value recorded in

Step 2.

If the issue is water temperature

uctuaons, check for the following:

• Verify the plumbing is reverse

return.

• Verify the outlet water tem-

perature of each acve water

heater via the P01 mode.

• Verify the ow rate through

each acve water heater via

the P03 mode. A reduced ow

rate by one heater may indi-

cate a clogged inlet lter, in-

sucient gas supply, too large

gas pressure drop, blocked

exhaust and/or intake, etc.

• Verify the C mode sengs are

accurate for the installaon.

• If a recirculaon system is set

up, verify the check valve on

the return line prior to the

inlet water tee is operang

correctly. An improperly oper-

ang check valve can reduce

the recirculaon pump’s ow

rate causing temperature

uctuaons.

10 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

COMPONENT TESTING AND DIAGNOSIS

COMPONENT DATA

Table 2: Acvaon ΔT and Flow Rates (TM-199 Series C0=0)

Acvaon: Altude 0 – 1,999 . (C0=0)

TM-160 (gpm) TM-180 (gpm) TM-199 (gpm)

ΔT

Units

< 60°F 60°F - 80°F > 80°F < 60°F 60°F - 80°F > 80°F < 60°F 60°F - 80°F > 80°F

1 to 2 3.7 2.6 2.0 4.1 2.9 2.3 4.6 3.2 2.6

2 to 3 7.4 5.3 4.1 8.3 5.9 4.7 9.2 6.5 5.1

3 to 4 11.0 7.9 6.1 12.4 8.8 7.0 13.7 9.7 7.7

4 to 5 14.7 10.5 8.1 16.5 11.7 9.3 18.3 12.9 10.2

5 to 6 18.4 13.1 10.1 20.6 14.6 11.6 22.9 16.1 12.8

6 to 7 22.1 15.8 12.2 24.8 17.6 14.0 27.5 19.4 15.3

7 to 8 25.7 18.4 14.2 28.9 20.5 16.3 32.0 22.6 17.9

8 to 9 29.4 21.0 16.2 33.0 23.4 18.6 36.6 25.8 20.4

9 to 10 33.1 23.6 18.2 37.1 26.3 20.9 41.2 29.0 23.0

10 to 11 36.8 26.3 20.3 41.3 29.3 23.3 45.8 32.3 25.5

11 to 12 40.4 28.9 22.3 45.4 32.2 25.6 50.3 35.5 28.1

Table 3: Deacvaon ΔT and Flow Rates (TM-199 Series C0=0)

Deacvaon: Altude 0 – 1,999 . (C0=0)

TM-160 (gpm) TM-180 (gpm) TM-199 (gpm)

ΔT

Units

< 60°F 60°F - 80°F > 80°F < 60°F 60°F - 80°F > 80°F < 60°F 60°F - 80°F > 80°F

12 to 11 32.3 23.1 18.1 36.3 25.7 20.6 40.4 28.1 22.4

11 to 10 29.3 21.0 16.4 33.0 23.3 18.7 36.7 25.6 20.3

10 to 9 26.4 18.9 14.8 29.7 21.0 16.8 33.0 23.0 18.3

9 to 8 23.5 16.8 13.1 26.4 18.7 14.9 29.3 20.5 16.3

8 to 7 20.6 14.7 11.5 23.1 16.4 13.1 25.7 17.9 14.3

7 to 6 17.6 12.6 9.8 19.8 14.0 11.2 22.0 15.4 12.2

6 to 5 14.7 10.5 8.2 16.5 11.7 9.3 18.3 12.8 10.2

5 to 4 11.8 8.4 6.5 13.2 9.4 7.4 14.6 10.3 8.2

4 to 3 8.9 6.3 4.9 9.9 7.1 5.6 11.0 7.7 6.2

3 to 2 5.9 4.2 3.2 6.6 4.7 3.8 7.4 5.2 4.1

2 to 1 2.9 2.1 1.7 3.3 2.3 1.9 3.7 2.6 2.0

Table 4: Acvaon ΔT and Flow Rates (TM-199 Series C0=1,2)

Acvaon: Altude 2,000 – 7,800 . (C0=1,2)

TM-160 (gpm) TM-180 (gpm) TM-199 (gpm)

ΔT

Units

< 60°F 60°F - 80°F > 80°F < 60°F 60°F - 80°F > 80°F < 60°F 60°F - 80°F > 80°F

1 to 2 2.5 1.8 1.4 2.8 2.0 1.6 3.1 2.2 1.7

2 to 3 4.9 3.5 2.7 5.5 3.9 3.1 6.1 4.3 3.4

3 to 4 7.4 5.3 4.1 8.3 5.9 4.7 9.2 6.5 5.1

4 to 5 9.8 7.0 5.4 11.0 7.8 6.2 12.2 8.6 6.8

5 to 6 12.3 8.8 6.8 13.8 9.8 7.8 15.3 10.8 8.5

6 to 7 14.7 10.5 8.1 16.5 11.7 9.3 18.3 12.9 10.2

7 to 8 17.2 12.3 9.5 19.3 13.7 10.9 21.4 15.1 11.9

8 to 9 19.6 14.0 10.8 22.0 15.6 12.4 24.4 17.2 13.6

9 to 10 22.1 15.8 12.2 24.8 17.6 14.0 27.5 19.4 15.3

10 to 11 24.5 17.5 13.5 27.5 19.5 15.5 30.5 21.5 17.0

11 to 12 27.0 19.3 14.9 30.3 21.5 17.1 33.6 23.7 18.7

Table 5: Deacvaon ΔT and Flow Rates (TM-199 Series C0=1,2)

Deacvaon: Altude 2,000 – 7,800 . (C0=1,2)

TM-160 (gpm) TM-180 (gpm) TM-199 (gpm)

ΔT

Units

< 60°F 60°F - 80°F > 80°F < 60°F 60°F - 80°F > 80°F < 60°F 60°F - 80°F > 80°F

12 to 11 32.3 23.1 18.1 24.2 17.1 13.7 26.9 18.8 14.9

11 to 10 29.3 21.0 16.4 22.0 15.6 12.5 24.5 17.1 13.6

10 to 9 26.4 18.9 14.8 19.8 14.0 11.2 22.0 15.4 12.2

9 to 8 23.5 16.8 13.1 17.6 12.5 10.0 19.6 13.7 10.9

8 to 7 20.6 14.7 11.5 15.4 10.9 8.7 17.1 12.0 9.5

7 to 6 17.6 12.6 9.8 13.2 9.4 7.5 14.7 10.3 8.2

6 to 5 14.7 10.5 8.2 11.0 7.8 6.2 12.2 8.6 6.8

5 to 4 11.8 8.4 6.5 8.8 6.3 5.0 9.8 6.9 5.5

4 to 3 8.9 6.3 4.9 6.6 4.7 3.7 7.3 5.2 4.1

3 to 2 5.9 4.2 3.2 4.4 3.1 2.5 4.9 3.5 2.7

2 to 1 2.9 2.1 1.7 2.2 1.6 1.3 2.5 1.7 1.4

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 11

COMPONENT TESTING AND DIAGNOSIS

COMPONENT DATA

12 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

OPERATION

Table 6: User Interface Display

Item Descripon

A Water Flow Detected

B Flame Detected

C Up Buon

D Down Buon

E Display

F Standby Mode

G Seng Buon

H Operaon ON/OFF Buon

Display Overview

ON/OFF

DOWN

UP SETTING

Figure 3 - User Interface Display Diagram

OPERATION

Temperature Sengs

With the installaon steps completed, you may adjust the water heater's temperature seng if desired. The water temperature

set point is factory set to 120°F (49°C). The temperature set point may be increased or decreased by simply pressing the

"UP" buon or the "DOWN" buon. To set the water heater to a temperature above 125°F (52°C), follow the procedure as

outlined in Table 7:

Table 7: Set Temperature Above 125°F (52°C)

Operaon Screen on the Controller (Built-in & Remote)

1. Turn on the 120 VAC power supply to the unit.

Press the "ON/OFF" buon on the controller in order to turn the

controller on.

ON/OFF

The set point temperature will display as shown in the picture on

the right (Example: 120°F).

WARNING! Higher temperatures increase the risk of scalding,

but even at 120°F (49°C), hot water can scald (page 10).

Press and hold the "SETTING" buon for 5 seconds to access the

water heater Adjustment Mode (A Mode).

LONG PRESS

SETTING

The display will ash between code "A00" and the current set

temperature. Short press the "SETTING" buon to access the

temperature seng. The temperature only will ash.

SHORT PRESS

SETTING

Press the "UP" buon and the "DOWN" buon to select the

desired set point temperature. See Table 18 below for available

set point temperatures.

DOWN

7. Short press the "SETTING" buon again to execute the change.

SHORT PRESS

SETTING

Press and hold the "SETTING" buon for 5 seconds to return the

display to normal operaon. The new temperature set point will

appear (Example: 130°F).

Table 8: Water Heater Temperature Set Points

°F 100 102 104 106 108 110 115 120* 125 130 135 140

°C 38 39 40 41 42 43 46 49* 52 54 57 60

*Factory seng (Default): 120°F (49°C).

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 13

OPERATION

14 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

OPERATION

Conguraon Mode (C Mode)

You can congure the water heater to accommodate your applicaon from C Mode. Follow the procedure below to access

C Mode and to properly congure the water heater for your applicaon:

1. Press and hold the "UP" buon and the "SETTING" buon for 5 seconds to access C Mode.

2. Press the "UP" buon or the "DOWN" buon to search for the desired C Code.

3. If applicable, press the "SETTING" buon to adjust the value of the C Code using the "UP" and "DOWN" buons. The value

will ash.

4. Press the "SETTING" buon again to conrm the new value selected is correct.

5. Press and hold the "UP" buon and the "SETTING" buon for 5 seconds to return the display to normal operaon.

Table 9: C Mode Altude Sengs (C01)

Code Descripon Seng Conguraon Opons

C01 Altude Sengs

0 0 to 2,000 . (0 to 610 m) Elevaon

1 2,001 to 5,400 . (611 to 1,645 m) Elevaon*

2 5,401 to 7,800 . (1,646 to 2,377 m) Elevaon*

*High altude vent sengs above 2000 (609 m) feet will impact some vent length sengs. See Table 12.

Table 10: C Vent Size (C08)

Code Descripon Seng Conguraon Opons

C08 Vent Size

2 2 Inch

3 3 Inch

Vent Length Conguraon

Before operang the water heater, you must determine the correct vent length seng for your applicaon:

Example:

Venlaon Component Type Equivalent Length

The example to the le assumes a

Power Direct Vent installaon with

2 inch Polypropylene venng at sea level.

Using Table 11 on the following page, the

appropriate C02 seng for 24 feet

(7.2 m) of venng is

C02 = 2.

Elbows (Table 8) (1x) 87° Elbow 3 . (0.9 m)

Terminaon (Tables 9 & 10) Polypropylene (2" Low Prole) 6 . (1.8 m)

Horizontal Vent Run Polypropylene 12 . (3.7 m)

Vercal Vent Run Polypropylene 3 . (0.9 m)

Total Vent Length: 24 . (7.3 m)

Your Applicaon:

Venlaon Component Type Equivalent Length

Use your total length and the informaon

found in Table 11 or Table 12 (depending

on elevaon) on the following page to

determine the correct vent length seng

based on your applicaon.

Elbows (Table 8)

Terminaon (Tables 9 & 10)

Horizontal Vent Run

Vercal Vent Run

Total Vent Length:

OPERATION

Table 11: C Mode Vent Length Conguraon (C02) for 0-2,000 . (0 to 610 m) Elevaon

Code

Vent

Material

Vent

Size

Vent

Conguraon

Controller Seng

C02 = 0 C02 = 1 C02 = 2 C02 = 3 C02 = 4

C02

PVC

2 Inch

PDV

4-7 .

(1.2-2.1 m)

8-18 .

(2.2-5.5 m)

19-31 .

(5.6-9.5 m)

32-44 .

(9.6-13.4 m)

45-50 .

(13.5-15.2 m)

4-12 .

(1.2-3.7 m)

13-25 .

(3.8-7.6 m)

26-50 .

(7.7-15.2 m)

3 Inch

PDV

4-20 .

(1.2-6.1 m)

21-60 .

(6.2-18.3 m)

61-140 .

(18.4-42.7 m)

141-150 .

(42.8-45.7 m)

4-25 .

(1.2-7.6 m)

26-80 .

(7.7-24.4 m)

81-150 .

(24.5-45.7 m)

2 Inch

PDV

4-9 .

(1.2-2.7m)

10-21 .

(2.8-6.4 m)

22-39 .

(6.5-11.9 m)

40-50 .

(12.0-15.2 m)

4-12 .

(1.2-3.7 m)

13-30 .

(3.8-9.1 m)

31-50 .

(9.2-15.2 m)

3 Inch

PDV

4-20 .

(1.2-6.1 m)

21-60 .

(6.2-18.3 m)

61-140 .

(18.4-42.7 m)

141-150 .

(42.8-45.7 m)

4-25 .

(1.2-7.6 m)

26-80 .

(7.7-24.4 m)

81-150 .

(24.5-45.7 m)

(PVC = Polyvinyl Chloride, PP = Polypropylene, PDV = Power Direct Vent, PV= Power Vent)

Table 12: C Mode Vent Length Conguraon (C02) for 2,001-7800 . (611 to 2,377 m) Elevaon

Code

Vent

Material

Vent

Size

Vent

Conguraon

Controller Seng

C02 = 0 C02 = 1 C02 = 2 C02 = 3 C02 = 4

C02

PVC

2 Inch

PDV

4-7 .

(1.2-2.1 m)

8-18 .

(2.2-5.5 m)

19-31 .

(5.6-9.5 m)

32-44 .

(9.6-13.4 m)

45-50 .

(13.5-15.2 m)

4-12 .

(1.2-3.7 m)

13-25 .

(3.8-7.6 m)

26-42 

(7.7-12.8 m)

43-50 .

(12.9-15.2 m)

3 Inch

PDV

4-25 .

(1.2-7.6 m)

26-70 .

(7.7-21.3 m)

71-150 .

(21.4-45.7 m

4-35 .

(1.2-10.7 m)

36-120 .

(10.8-36.6 m)

121-150 .

(36.7-45.7 m)

2 Inch

PDV

4-9 .

(1.2-2.7m)

10-21 .

(2.8-6.4 m)

22-39 .

(6.5-11.9 m)

40-50 .

(12.0-15.2 m)

4-12 .

(1.2-3.7 m)

13-30 .

(3.8-9.1 m)

31-50 .

(9.2-15.2 m)

3 Inch

PDV

4-25 .

(1.2-7.6 m)

26-70 .

(7.7-21.3 m)

71-150 .

(21.4-45.7 m

4-35 .

(1.2-10.7 m)

36-120 .

(10.8-36.6 m)

121-150 .

(36.7-45.7 m)

(PVC = Polyvinyl Chloride, PP = Polypropylene, PDV = Power Direct Vent, PV= Power Vent)

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 15

OPERATION

16 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

OPERATION

Cascade System Conguraon

Table 13: C Mode Cascade System (C13 & C14)

Code Descripon Seng Conguraon Opons

C13 Number of Child Units in Cascade System

1-11:

No Cascade System (default).

Idenfy number of Child Units. This acvates the Cascade System.

C14 Cascade System Heater ID Number

2-12:

Parent Heater (default).

Individually set each Child Unit per user preference.

Unit Conversion Mode

Units of measure can be changed from Imperial to Metric and vice versa. For example, temperature can be changed from

°F to °C. Flow rate will also change from gallons per minute to liters per minute when this seng is changed. Follow this

procedure to change this seng:

Table 14: Convert Units

Operaon Screen on the Controller (Built-in & Remote)

1. Turn on the 120 VAC power supply to the unit.

Press the "ON/OFF" buon on the controller in order to turn the

controller on.

ON/OFF

The set point temperature will display as shown in the picture on

the right (Example: 120°F).

Press and hold the "SETTING" buon for 5 seconds to access the

water heater Adjustment Mode (A Mode).

LONG PRESS

SETTING

The display will ash between code "A00" and the current set

temperature. Press the "UP" or "DOWN" buon once and the

display will show code "A01." Short press the "SETTING" buon

to show the current temperature seng. The temperature will

ash.

SHORT PRESS

SETTING

Press the "UP" buon and the "DOWN" buon to alternate

between Fahrenheit and Celsius.

DOWN

7. Short press the "SETTING" buon again to execute the change.

SHORT PRESS

SETTING

Long press the "SETTING" to return the display to normal

operaon. The new temperature set point will appear in the

selected unit (Example: 49°C).

OPERATION

Informaon Mode (P Mode)

Follow the procedure below to access P Mode:

1. Press and hold the "UP" buon and the "DOWN" buon for 5 seconds to access P Mode.

2. Press the "UP" buon or the "DOWN" buon to search for the desired P Code.

3. Press and hold the "UP" buon and the "DOWN" buon for 5 seconds to return the display to normal operaon.

Table 15: P Mode Sengs (P00 - P23)

Code Descripon Value

P00 Heat Exchanger Water Outlet Temperature °F / °C

P01 Water Outlet Temperature °F / °C

P02 Water Inlet Temperature °F / °C

P03 Water Flow 0.1* gpm OR 0.1* L/min

P04 Fan Speed The real-me Fan speed (RPM)

P05 Fan Current (mA)

P06 Proporonal Valve Current (mA)

P07 Bypass Water Valve Posion

The real-me posion of bypass valve

(0 = full open; 2200 = full closed)

P08 Main Water Valve Posion

The real-me posion of main water valve

(0 = full open; 2200 = full closed)

P09 A/D Value Of Flame

Flame sensor signal:

• Less than 140 in standby

• Greater than 180 under combuson

(this value increases as input increases)

P12 Most Recent Fault Code

Fault codeP13 Second Most Recent Fault Code

P14 Third Most Recent Fault Code

P15 Exhaust Temperature °F / °C

P16 Display Soware Version No. Front board soware version

P17 Controller Soware Version No. Main board soware version

P19 Model Number 199/180/160/140

P20 Combuson Time

Combuson me in hours. The UIM will display up to 4 digits (2

second pause) and the remaining 4 digits. See Figure 4.

P21 Ignion Quanty

Number of mes the ignitor has acvated. The UIM will display up to

4 digits (2 second pause) and the remaining 4 digits. See Figure 4.

EXAMPLE:

Join the two values (not add) to create the total: 231,971 then x 100 will yield 23,197,100 gallons.

2 Second

Pause

2 Second

Pause

First four digits.

Second four digits.

Figure 4 - Combining mulple display value data. Both 8 and 5 units.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 17

OPERATION

Descaling

During operaon, a tankless water

heater (supplied with hard water)

accumulates hard water deposits

on the interior surfaces of the heat

exchanger. These deposits make it

dicult to transfer heat into the

water, lowering the water heater’s

eciency and causing excessive wear

to the components. Removing any

deposits is essenal to the proper

operaon and longevity of the water

heater. The X3 model should not

require descaling, however, if you

choose to descale the water heater

you must use the Bypass cartridge. A

Bypass cartridge can be ordered from

the manufacturer, p/n: 100374700.

NOTICE: DO NOT descale the water

heater using the X3 cartridge as this

may damage the cartridge media. See

page 21 for instrucons on how to

remove the X3 and install the Bypass.

The water heater has a descaling

mode that will do the following to

help descale the water heater:

• Locks out the heater ring operaon

so the heater remains in standby

mode

• The ow control valve will stay in

the fully open posion

• The bypass water valve will move to

the fully closed posion to force the

descaling soluon through the heat

exchanger.

• The freeze protecon system will

not be acvated.

Tools and Materials:

• Submersible transfer pump

• 3 gallons of 5% acidity white vinegar

(food grade), available from most

grocery stores

• Washing machine hoses (2x)

• 5 gallon bucket

• Water heater isolaon valve kits,

installed on both the cold water

inlet and hot water outlet of the

water heater X3 Bypass Cartridge

(see Figure 6).

Descaling Procedure:

Close the isolaon valves (C &

D) to stop the main inlet and

outlet ow of water to the house (see

Figure 6).

Pour the white vinegar

(3 gallons) into the 5 gallon

bucket (see Figure 7).

Connect inlet hose to the

transfer pump's discharge

outlet. Connect the opposite end of

hose to the inlet hose connecon at

the cold water inlet's isolaon valve

(see Figure 7).

Place the pump in the bucket

of vinegar.

Connect the second hose to the

outlet hose connecon at the

hot water outlet. Place the loose end

of hose into the bucket with the

vinegar (see Figure 7).

Open the hot and cold service

valves A & B (see Figure 7).

Acvate the water heater's

descaling mode by accessing C

Mode.

A. Simultaneously press and hold

the UP arrow and the SETTING

buon for approximately 6

seconds.

B. The display will ash C00.

C. Press the UP buon or DOWN

buon to cycle to C15.

D. Press the SETTING buon (the

display will ash OFF).

E. Press the UP buon or DOWN

buon to cycle to "dScl" (see

Figure 5).

F. Press the SETTING buon to

acvate the descaling mode.

Figure 5 - UIM display

Turn power to the pump on

and let it run for approximately

45 minutes.

Shut OFF power to the pump

when descaling is complete.

Close service valves A & B (see

Figure 7).

If possible, connect the outlet

hose to a drain or outside in

order to ush the water heater. If

unable, go to Step 13.

Open valve A to ush the water

heater and remove loose scale

and vinegar. Suggested ush me is

approximately 10 minutes. Proceed to

Step 15.

If unable to relocate the outlet

hose to a drain or outside,

conrm valves A & B are closed.

Open valves C & D.

Open the nearest hot water

xture to ush the water

heater of any remaining vinegar.

Suggested ush me is approximately

10 minutes.

NOTICE: DO NOT use a combined hot

and cold xture typically found in a

shower.

When ushing is complete,

close all valves and remove all

hoses.

Press the SETTING buon on

the water heater's controller.

Use the UP buon or DOWN

buon to change the display

from "dScl" to "OFF."

Press the SETTING buon on

the water heater's controller.

Simultaneously press and hold

the UP buon and SETTING

buon for approximately 6 seconds to

enter normal operang mode.

Turn ON the gas supply valve.

Open valves C & D.

Open the nearest hot water

xture for a short me to

test-re the heater and conrm there

are no issues.

18 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

MAINTENANCE

Expansion

Tank

Isolation Valve (C)

Isolation Valve (D)

CWS

NOTE: Condensate Drain not shown for clarity.

Water

Shutoff

Valve

HWS

Gas Line

Bypass

Cartridge

Bypass

Cartridge

DO NOT descale the water

heater using the X3 cartridge.

Inlet Hose

Connection

Outlet Hose

Connection

(B)

(A)

Figure 6 - Descaling the water heater

Isolation

Valve (C)

Isolation

Valve (D)

Hot

Service

Valve (A)

Cold

Service

Valve (B)

Outlet Hose

Connection

Inlet Hose

Connection

5 Gallon

Bucket

Submersible

Pump

3 Gallons

White Vinegar

(Food Grade)

Outlet

Hose

Inlet Hose

Figure 7 - Isolaon valve connecon points

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 19

MAINTENANCE

Unit Draining &

Power Outage (Freeze

Protecon)

Close the manual gas shut-o valve.

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box.

Close the cold inlet water valve.

Open all hot water taps in the

house. When the residual

water ow has ceased, close all hot

water taps.

Drain the X3® (or Bypass)

Cartridge: Have a bucket or pan

to catch water from the X3® Cartridge.

To remove the X3® Cartridge, remove

and keep the 3 screws securing the

cartridge in place. Pull down to

remove it from the water heater.

Empty the water out of the cartridge

into the bucket.

Wait a few minutes to ensure

all water has completely

drained from the unit.

Keep the cold water valve

closed. Keep the gas valve

closed. Keep supply power

disconnected.

To restore the unit to

operaon, reinstall the X3®

Cartridge with 3 screws removed

earlier. For detailed instrucons see

the “X3® & Bypass Cartridge” secon

on page 21.

Open the cold inlet water valve.

Check all water connecons for

leaks. If leaks are found, shut o the

cold water inlet valve and immediately

x any leaks. If no leaks are present

proceed to the next step.

Reconnect power to the water

heater.

Open the manual gas shut-o

to the water heater.

If the set temperature is not

displayed, press the ON/OFF

buon.

NOTICE: If any errors occur, shut o

the water immediately.

Discharge Condensate

Inspect the drain lines for any

clogs and clear.

Check the drain lines for a

downward slope. Correct any

lines where water does not drain

freely.

Inspect the built-in condensate

trap drain lines for debris.

Disconnect the lines and drain to

remove the debris.

If a neutralizer is installed,

check the pH level. Replace the

neutralizer if the pH of the outlet

water is below 6.0.

If this lter is clogged, water

will not be supplied to the

water heater properly.

Inlet Water Filter

Close the manual gas shut-o

valve.

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box.

Close the inlet water valve.

Open all hot water taps in the

house. When the residual

water ow has ceased, close all hot

water taps.

Drain the X3® (or Bypass)

Cartridge: Have a bucket or pan

to catch water from the X3® Cartridge.

To remove the X3® Cartridge, remove

and keep the 3 screws securing the

cartridge in place. Pull down to

remove it from the water heater.

Empty the water out of the cartridge

into the bucket.

Wait a few minutes to ensure

all water has completely

drained from the unit.

Unscrew the inlet water lter

and remove it from the water

heater.

Clean the lter: Check the

water lter located within the

cold inlet. With a ny brush, clean the

water lter of any debris which may

have accumulated.

Screw the inlet water lter back

into place. Hand- ghten only.

NOTICE: Handle with care and verify

the O-ring is not dirty or damaged.

To restore the unit to

operaon, reinstall the X3®

Cartridge with 3 screws removed

earlier. For detailed instrucons see

the “X3® & Bypass Cartridge” secon

on page 21.

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater. The water heater is now

ready for operaon.

20 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

MAINTENANCE

X3® & Bypass Cartridge

Removing the Old Cartridge

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Locate the three screws

securing the X3®/Bypass

cartridge. Remove the

M4-12mm

screw and the two

M4-25mm

screws from cartridge. Place screws

aside in a safe place for reinstallaon.

See Figure 8 and Figure 9.

A BB

ALIGN

CARTRIDGE

MANIFOLD

ARROWS ARE FACING BACKSIDE

Figure 8 - X3® Cartridge

A BB

MANIFOLD

BYPASS CARTRIDGE

Figure 9 - Bypass Cartridge

NOTICE: If you have the cartridge

an-freeze kit installed, remove and

set it aside for reinstallaon later.

With the screws removed, pull

down to remove the cartridge

from the water heater. Place a bucket

under the water heater cabinet to

collect any residual water.

NOTICE: The cartridge will be full

of water. Use cauon not to lt the

cartridge unl the water has been

drained.

Installing the New Cartridge:

Inspect the new cartridge and

O-rings for damage or debris.

Verify lubricant has been properly

applied to O-rings.

Insert the cartridge into

manifold.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (arrows will be back

facing for TM series heaters). When

inserng the cartridge, push up unl

the screw holes align. Some resistance

is normal. The bypass cartridge is

not keyed and will install in either

direcon. Figure 8 and Figure 9.

Insert and snug all three screws

by hand. Use a screwdriver to

ghten the two

screws rst and

lastly ghten screw

. DO NOT use a

drill or impact driver to ghten the

screws.

NOTICE: Use only the screws removed

earlier and note their order. They are

not interchangeable with any other

type of screw.

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 21

MAINTENANCE

22 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

TROUBLESHOOTING

General Troubleshoong

If the water heater is experiencing issues, please check the following.

Table 16: Troubleshoong Chart

Problem Soluons

Temperature and Amount of Hot Water

It takes a long me to get hot water

at the xtures.

• The mes it takes to deliver hot water from the water heater to your xtures

depends on the length of piping between the two. The longer the distance or

the bigger the pipes, the longer it will take to get hot water.

• If you would like to receive hot water to your xtures more quickly, you may

want to consider a hot water recirculaon system.

The water is not hot enough.

• Check the set temperature of the water heater and adjust, if necessary.

• Check cross plumbing between the cold water lines and hot water lines.

• Is the gas supply valve open fully?

• Is the gas line sized properly?

• Is the gas supply pressure sucient?

• Check if the Point-of-Use mixing valves are set correctly if they are installed.

The water is too hot. • Is the set point temperature set too high?

The hot water is not available when

a xture is opened.

• Make sure the unit has 120 VAC, 60 Hz power supply and power frequency is

set to 60 hz.

• Verify the operaon seng is ON by viewing the UIM. If the set temperature

is showing, or you press the UP arrow to display the set temperature, then the

operaon seng is ON. If the display is blank and nothing appears when press-

ing the UP buon, then the operaon state is set to OFF. Press the ON/OFF

buon to acvate the heater. The set temperature will display when set to ON.

• Is the gas supply valve open fully and within the allowable gas pressure range?

• Is the water supply valve fully open?

• Is the lter on the cold water inlet clean?

• Is the hot water xture suciently open to draw at least 0.4 GPM (1.5 L/min)

through the water heater?

• Is the unit frozen?

The hot water runs cold and stays

cold.

• Is the ow rate enough to keep the water heater running?

• If there is a recirculaon system installed, does the recirculaon line have

enough check valves?

• Is the gas supply valve fully open?

• Is the lter on the cold water inlet clean?

• Are the xtures clean of debris and obstrucons?

Fluctuaon in hot water

temperature.

• Is the lter on the cold water inlet clean?

• Is the gas line sized properly?

• Is the gas supply pressure sucient?

• Check for cross connecon between cold water lines and hot water lines.

• If cascaded with mulple heaters, inspect and verify each heater is operang

properly within the cascade system.

TROUBLESHOOTING

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 23

Table 16: Troubleshoong Chart

Problem Soluons

Water Heater

Unit does not ignite when water

goes through the unit.

• Is the ow rate over 0.4 GPM (1.5 L/min)?

• Check the lter on the cold water inlet.

• Check for reverse connecons and cross connecon.

• If you use the remote controller and/or built-in controller, is the power buon

turned on?

• Check if the inlet water temperature is too high. If it is too close to the set tem-

perature, the water heater will not acvate.

The fan motor is sll spinning aer

operaon has stopped.

• This is normal. Aer operaon has stopped, the fan motor keeps running to

re-ignite quickly, as well as to purge all the exhaust gas out of the ue.

Unit sounds abnormal while in

operaon.

• Check all venng and terminaons for any blockage and clear.

• If other exhaust terminaons are nearby, conrm ue gases are not sucked into

the water heater's air intake.

TROUBLESHOOTING

24 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

TROUBLESHOOTING

Error Codes

The water heater has self-diagnosc

funcons for safety and convenience

when troubleshoong.

If there is a problem with the

installaon or the unit, the error code

associated with that failure will be

displayed on the built-in controller or

remote controller.

Consult Table 17 on the following

pages for the descripon of each error

code.

Single Unit Installaon

(Example)

If your water heater has the "E002"

error code (which signies a high limit

break):

• Indicator on the built-in and/or

remote controller will display "E002"

on the screen.

Figure 10 - Single Unit Error Code Example

Cascade System

(Example)

Error codes will be displayed

dierently with units installed within

a Cascade System, not only to show

what the error code is, but to also

indicate which unit within the system

has the error code. Below is a sample

of how the error code "E002" is

displayed in a Cascade System.

If Unit #2 has the "E002" error code

(which signies a high limit break):

• Indicator on the built-in and/or

remote controller of Parent unit will

intermiently ash "E002" and "2."

Figure 11 - Cascade System Error Code Example

(Parent Unit)

• Child unit #2 will intermiently ash

"E002" on the display.

Figure 12 - Cascade System Error Code Example

(Child Unit)

• Child unit #3 & #4 will not display

anything, as the error code does not

pertain to them.

TROUBLESHOOTING

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 25

TROUBLESHOOTING

Fault Analysis of Error Codes

If the water heater is displaying an error code, please check the following.

Table 17: Error Code Fault Analysis

Error

Code

Error Descripon Procedure

E002 High Limit Break

1. Visual inspecon: connecon/breakage of wires. Possibility also includes scale

deposits inside the heat exchanger if using an M model.

2. Manual Hi-Limit Switch on water outlet tripped. Check the switch for proper opera-

on. Press the reset buon (center of the switch), to reset it.

NOTICE: You will hear and feel the switch click when reseng it. If the hi-limit

switch connues to trip replace the hi-limit switch.

3. M Model: If water heater is installed in a hard water area the manual hi-limit switch

may trip due to scaling.

E006

PCB Hardware Fault - AD

Converter Fault

Check PCB wiring for loose, damaged or cut wires/connectors. Correct any loose

connecon and replace any damaged wires/connectors. If all wires/connectors are

intact, replace the PCB.

E010 Frequency Fault

1. PCB has detected an incorrect power supply frequency. Note the default frequency

is 60 Hz. Conrm that C07 is set to the correct frequency of the supply power. See

Table 6 to access modes.

• if C07 = 60 (48 < X < 72)

• if C07 = 50 (40 < X < 60)

2. If the seng is correct and the error sll occurs, check supply to conrm frequency

range.

E011

PCB Hardware Fault -

Memory Error

The water heater will connue to operate while this error code is ashing. If this heater

is part of a cascade system, then the system will be aected based on the heater’s

seng. PCB must be replaced on impacted heater.

• Parent Heater: The cascade system will not operate. Remove this heater from the

cascade system and set a dierent heater as the Parent.

• Child Heater: This heater will not operate. The rest of the cascade system will connue

to run.

TROUBLESHOOTING

26 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

TROUBLESHOOTING

Table 17: Error Code Fault Analysis

Error

Code

Error Descripon Procedure

E036 Flame Failure

WARNING! Working on an energized circuit can result in severe injury or death from

electrical shock.

1. Verify that the gas supply pressure is within specicaons when the heater is in

standby, and verify the gas pressure does not drop below the minimum specied

supply pressure when all gas appliances are in operaon. Also, verify that the gas

line is cleared of debris.

• It is possible that there is a faulty pressure regulator at the gas meter.

• If a second stage regulator is installed, verify the following: that it is sized

properly for the applicaon; that it is installed per the manufacturer’s instruc-

on (pay close aenon if an indoor vent limiter is installed); the vent line (if

installed) is sized properly. NOTICE: Some manufacturers may recommend that

a specic amount of straight pipe is installed on the regulator outlet before any

changes in direcon. Refer to the regulator’s manufacturer.

2. Check for blockages in venng, such as bird nests, animals, or trash. A blockage

will cause improper operaon leading to reduced capacity and inability to maintain

combuson.

3. If ame ignites for only 1-2 seconds before going out, verify that the red

"Flame Detected" ame indicator on the built-in controller or remote controller did

not turn on. If the ame indicator stayed o, then inspect the ame sensor. Clean it

if necessary. Replace it if any damage is seen.

E037

False Flame Detecon

(During Standby)

WARNING! Working on an energized circuit can result in severe injury or death from

electrical shock.

1. Verify the gas supply pressure is not above the specied maximum pressure. If it is,

troubleshoot and correct the gas supply system.

2. Check the error code history, P modes P12, P13, P14 and document the codes.

• If E384 is in the list, replace the gas valve.

• If E412 or E414 appear, replace the PCB.

• If E413 or E417 appear, inspect the ame sensor rod for dirt, debris, or dam-

age. Clean or replace the ame sensor. If either code appears again, replace the

PCB. NOTICE: You must run water through the heater for a minimum of

3 minutes at a minimum of 1 GPM to check for E417.

TROUBLESHOOTING

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 27

TROUBLESHOOTING

Table 17: Error Code Fault Analysis

Error

Code

Error Descripon Procedure

E038 Ignion Failure

WARNING! Working on an energized circuit can result in severe injury or death from

electrical shock.

1. Verify that the gas supply pressure is within specicaons when the heater is in

standby, and verify the gas pressure does not drop below the minimum specied

supply pressure when all gas appliances are in operaon. Also, verify that the gas

line is cleared of debris. For Propane installaons, verify the propane tank level is

not too low.

• It is possible that there is a faulty pressure regulator at the gas meter.

• If a second stage regulator is installed, verify the following: that it is sized

properly for the applicaon; that it is installed per the manufacturer’s instruc-

on (pay close aenon if an indoor vent limiter is installed); the vent line (if

installed) is sized properly. NOTICE: Some manufacturers may recommend that

a specic amount of straight pipe is installed on the regulator outlet before any

changes in direcon. Refer to the regulator’s manufacturer.

2. Check for blockages in venng, such as bird nests, animals, or trash. A blockage

will cause improper operaon leading to reduced capacity and inability to maintain

combuson.

3. If ame ignites for only 1-2 seconds before going out, verify that the red

"Flame Detected" ame indicator on the built-in controller or remote controller did

not turn on. If the ame indicator stayed o, then inspect the ame sensor. Clean it

if necessary. Replace it if any damage is seen.

E041 Outlet Water Over-temp

1. Verify the thermistor reading with the water outlet temperature. See "Thermistor

Resistance Vs Temperature Charts" on page 121.

2. Remove the outlet thermistor (do not lose the O-ring) and check for any dirt or

debris. Clean with an Emery cloth. If the thermistor is damaged, replace it. Check

all venng for any blockage and clear. Verify gas pressure and supply and if failure

persists replace gas valve.

E049 Exhaust Thermistor Failure

1. Remove the thermistor (do not lose the O-ring) and check for any dirt or debris.

Clean with an Emery cloth. If the thermistor is damaged, replace it.

2. Check the Thermistor sensor wire for a short or disconnecon. Correct any loose

connecons and replace any damaged wire/connector or thermistor assembly.

3. Check all venng (intake/exhaust) for an blockages and clear as necessary. Verify

gas pressure and supply. If failure persists, replace gas valve.

E050 Inlet Thermistor Failure

1. Remove the thermistor (do not lose the O-ring) and check for any dirt or debris.

Clean with an Emory cloth. If the thermistor is damaged, replace it.

2. Check the Thermistor sensor wire for a short or disconnecon. Correct any loose

connecon and replace any damaged wire/connector.

TROUBLESHOOTING

28 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

TROUBLESHOOTING

Table 17: Error Code Fault Analysis

Error

Code

Error Descripon Procedure

E051 Outlet Thermistor Failure

1. Remove the thermistor (do not lose the O-ring) and check for any dirt or debris.

Clean with an Emory cloth. If the thermistor is damaged, replace it.

2. Check the Thermistor sensor wire for a short or disconnecon. Correct any loose

connecon and replace any damaged wire/connector. If the error sll occurs, con-

tact a qualied service technician.

E052

Heat Exchanger Thermistor

Failure

1. Remove the thermistor (do not lose the O-ring) and check for any dirt or debris.

Clean with an Emory cloth. If the thermistor is damaged, replace it.

2. Check the Thermistor sensor wire for a short or disconnecon. Correct any loose

connecon and replace any damaged wire/connector.

3. Check all venng (intake/exhaust) for an blockages and clear as necessary. Verify

gas pressure and supply and if failure persists replace gas valve.

E381 Combuson Blockage

1. With the water heater power disconnected, check the exhaust vent and air intake

piping for any blockages. Remove any blockages.

2. Verify the water heater has sucient combuson air. Reference the Combuson

and Venng Installaon secon of the manual.

3. If the error sll occurs, contact a qualied service technician.

E382

Abnormal Proporonal

Valve Current

Check the proporonal valve wiring. Correct any loose connecon and replace any

damaged wire/connector. If the error sll occurs, contact a qualied service technician.

E383 Inlet Water Over-temp

1. Verify the inlet water temperature is not above the water heater's set temperature.

2. Remove the thermistor (do not lose the O-ring) and check for any dirt or debris.

Clean with an Emory cloth. If the thermistor is damaged, replace it.

3. Check the Thermistor sensor wire for a short or disconnecon. Correct any loose

connecon and replace any damaged wire/connector. If the error persists, replace

thermistor.

E385

Main Gas Solenoid Valve

Drive Circuit Failure

The PCB detects an incorrect voltage from the gas valve solenoid valve. Correct any

loose connecons and replace any damaged wire/connector.

E388 Bypass Valve Fault

1. Correct any loose connecon and replace any damaged wire/connector.

2. Follow the draining procedure in the installaon manual to properly drain the water

heater. Remove the Bypass valve and inspect for any debris or damage. Replace if

needed.

E389 Fan Current AD Failure Replace the PCB.

E390

Fan Over Max Current

(During Standby)

Check the fan motor wiring. Correct any loose connecon and replace any damaged

wire/connector. If the error sll occurs, contact a qualied service technician.

E391

Fan Over Max Current

(During Operaon)

Check the fan motor wiring. Correct any loose connecon and replace any damaged

wire/connector. If the error sll occurs, contact a qualied service technician.

TROUBLESHOOTING

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 29

Table 17: Error Code Fault Analysis

Error

Code

Error Descripon Procedure

E392

Fan False Start

(During Operaon)

Check the fan motor wiring. Correct any loose connecon and replace any damaged

wire/connector.

E393 Fan Signal Loss

Check the fan motor wiring. Correct any loose connecon and replace any damaged

wire/connector.

E394 Fan Target Speed

1. Check the fan motor wiring. Correct any loose connecon and replace any damaged

wire/connector.

2. With the water heater power disconnected, check the exhaust vent and air intake

piping for any blockages. Remove any blockages.

E395

Fan Current without Drive

(During Standby)

Check the fan motor wiring. Correct any loose connecon and replace any damaged

wire/connector. If the error sll occurs, contact a qualied service technician.

E400

Communicaon Fault with

UIM

1. Check the UIM wiring. Correct any loose connecon and replace any damaged wire/

connector.

2. If UIM is displaying, replace the PCB. If UIM is not displaying, replace the UIM.

E401

Communicaon Fault with

Remote Controller

1. Check the Remote Controller wiring. Correct any loose connecons and replace any

damaged wire/connector.

2. Only one remote controller can be installed. Remove any addional remote control-

lers.

3. If the error sll occurs and remote is displaying values, then replace the PCB.

E402

Communicaon Fault in

Cascade System

1. Check the Cascade wiring. Correct any loose connecons and replace any damaged

wire/connector.

2. Cycle the child heater’s power OFF/ON if the cascade wiring was disconnected

while the system sll had power.

3. If the error sll persists, verify parent heater PCB funconality. Replace PCB if nec-

essary.

E404

Inconsistent Models in

Cascade-Link

Conrm all units in Cascade System are the same model. All models in the cascade

system must be the same.

E412

PCB Hardware Fault - Flame

Circuit Failure

Replace the PCB.

TROUBLESHOOTING

Table 17: Error Code Fault Analysis

Error

Code

Error Descripon Procedure

E413 Flame Sensor Fault

1. Verify the water heater is properly grounded?

2. Check the ame sensor wire for a short or disconnecon. Correct any loose connec-

ons and replace any damaged wire/connector.

3. With the water heater power disconnected, check the exhaust vent and air intake

piping for any blockages. Remove any blockages.

4. Verify the water heater has sucient combuson air, reference the Combuson and

Venng Installaon secon in the installaon manual.

5. Check the installaon area for corrosive elements, reference the see Installaon

Environment secon in the installaon manual.

6. Remove and inspect the ame sensor, check for any dirt or debris. Clean with Em-

ery cloth. If error persists, replace ame sensor.

E414 PCB - Flame Sensor Circuit

1. Check the ame sensor wire for a short or disconnecon. Correct any loose connec-

on and replace any damaged wire/connector.

2. If the error sll occurs, replace the PCB.

E416

Analog/Digital (AD) Value

Fault

1. Check the outlet thermistor sensor wire for a short or disconnecon. Correct any

loose connecons and replace any damaged wire/connector.

2. Remove the outlet thermistor (do not lose the O-ring) and check for any dirt or

debris. Clean with an Emery cloth. If the thermistor is damaged, replace it.

3. If the error sll occurs, replace the PCB.

E418 Exhaust High Temperature

1. With the water heater power disconnected, check the exhaust vent and air intake

piping for any blockages. Remove any blockages.

2. Remove the exhaust thermistor (do not lose the O-ring) and check for any dirt or

debris. Clean with Emory cloth. If the thermistor is damaged, replace it.

3. Check all venng (intake/exhaust) for an blockages and clear as necessary. Verify

gas pressure and supply. If failure persists, replace gas valve.

E419 Flame Signal Lost

1. Check the ame sensor wire for a short or disconnecon. Correct any loose

connecon and replace any damaged wire/connector.

2. With the water heater power disconnected, check the exhaust vent and air intake

piping for any blockages. Remove any blockages. If the error sll occurs, contact a

qualied service technician.

3. If the error sll occurs, contact a qualied service technician.

30 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

TROUBLESHOOTING

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 31

Table 17: Error Code Fault Analysis

Error

Code

Error Descripon Procedure

E426 Condensate Drain Overow

1. Place a bucket under the water heater to catch any water.

2. With the water heater o, check the condensate drain for any blockages. Remove

any blockages.

3. Check the condensate drain wires for a short or disconnecon. Correct any loose

connecon and replace any damaged wire/connector.

4. Verify the condensate drain line is installed correctly, reference the installaon

manual.

E427 Flow Control Valve

1. Check the ow control valve wires for a short or disconnecon. Correct any loose

connecons and replace any damaged wire/connector.

2. Drain the water heater following the Unit Draining & Power Outage secon in the

installaon manual.

3. Remove the ow control valve and inspect for any debris or damage. Replace if

needed.

E428 Flow Sensor - Cascade Only

1. Verify the water heater’s operaon is enabled. The heater’s UIM will display the set

temperature when enabled. If it is disabled, press the heater’s ON/OFF buon to

enable the heater’s operaon.

2. Verify that the heater’s water shuto valves are open.

3. Check the ow sensor wires for a short or disconnecon. Correct any loose connec-

ons and replace any damaged wire/connector.

4. Drain the water heater following the Unit Draining & Power Outage secon in the

installaon manual.

5. Remove the ow sensor and inspect for any debris or damage. Replace if needed.

6. Remove and clean the inlet water lter. Replace if needed.

E429

Flow Control Valve Fault -

Cascade Only

1. Check the ow control valve wires for a short or disconnecon. Correct any loose

connecons and replace any damaged wire/connector.

2. Drain the water heater following the Unit Draining & Power Outage secon in the

installaon manual.

3. Remove the ow control valve and inspect for any debris or damage. Replace if

needed.

TROUBLESHOOTING

User Interface Module

& Wire Harness

Kit 100390075 Contains:

• User Interface Module (UIM)

• Kit Instrucons

Kit 100390076 Contains:

• UIM Wire Harness

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Accessing Water Heater

Components

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Replacing the User Interface

Module (Kit 100390075)

Locate the User Interface

Module (UIM). See Figure 13.

Printed

Circuit

Board

User Interface

Module

Figure 13 - Locang UIM

Gently li UIM upward to

release from boom of bracket

and remove UIM from bracket.

Disconnect wire harness from

UIM. See Figure 14.

Disconnect

Wiring

Harness

UIM Wire Routed

Through Bracket

Figure 14 - Disconnecng UIM

If replacing the User Interface

Module, dispose of it properly.

Locate the new UIM provided in the

kit and proceed to Step 14.

If replacing the UIM wire only,

place UIM aside in a safe place for

reinstallaon and proceed to the next

secon.

Replacing the User Interface

Module Wire (Kit 100390076)

Locate the Printed Circuit Board

on the right side of the water

heater. Use a Phillips screwdriver to

remove the two screws securing the

PCB. Place screws aside in a safe place

for reinstallaon. See Figure 15.

Remove

2 screws

Printed Circuit Board

Figure 15 - Removing PCB screws

Gently slide PCB out from

water heater.

Using Figure 16 as reference,

disconnect the UIM wiring

harness from PCB.

32 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

UIM

Connection

Point

Figure 16 - Disconnecng UIM from PCB

Remove UIM wire harness from

water heater. Take note of how

wire harness is routed for easy

installaon of new wire harness.

Locate the new wire harness

provided in the kit. Connect the

wire harness to the PCB and route the

wiring behind the gas valve and

through the boom opening of the

UIM bracket. See Figure 14 for

reference.

With the wiring harness

secured, slide PCB back into

posion and secure PCB to mounng

brackets with the two screws

previously removed in Step 8.

Replacing the User Interface

Module

Connect wire harness to UIM.

Slide UIM upward into slot in

bracket, then gently push downward

to secure UIM to bracket.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 2.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 33

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

34 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (ELECTRONIC & WIRING COMPONENTS)

Hi-Limit Switch

(Manual Reset)

Kit 100390070 Contains:

• Hi-Limit Switch (Manual Reset)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Accessing Water Heater

Components

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Removing Hi-Limit Switch

Locate the hi-limit switch on

the heat exchanger (top right

side of water heater). Disconnect the

two wire leads (labeled HIGH LIMIT 1)

from the hi-limit switch. See Figure

17.

Screw

Wire

Lead

Wire

Lead

Figure 17 - Hi-Limit switch locaon

Use a Phillips screwdriver to

remove the two screws

securing the hi-limit switch to the

heat exchanger. Place screws aside in

a safe place for reinstallaon. See

Figure 17.

Remove hi-limit switch from

heat exchanger and dispose of

properly.

Installing New Hi-Limit Switch

Locate the new hi-limit switch

assembly provided in the kit.

Install the hi-limit switch to the

heat exchanger. Secure with

the two screws previously removed in

Step 5. Conrm hi-limit switch sits

ush against heat exchanger.

Connect the two wire leads to

the hi-limit switch previously

disconnected in Step 4. Conrm wire

connecons are secure.

Returning the Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 2.

Restore power to the water

heater. The water heater is now

ready for operaon.

SERVICE

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 35

SERVICE (ELECTRONIC & WIRING COMPONENTS)

Freeze Protecon

Thermostat

Kit 100390078 Contains:

• Freeze Protecon Thermostat

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Removing Freeze Protecon

Thermostat

Locate the freeze protecon

thermostat wiring harness as

shown in Figure 18.

Remove the freeze protecon

thermostat from the outlet

piping by gently pulling on metal

clamp.

Press Here

Thermostat

Wiring Harness

Figure 18 - Freeze protecon thermostat

locaon

Disconnect the freeze

protecon thermostat wiring

harness. See Figure 18.

NOTICE: Press in the locaon shown

in Figure 18 to disconnect the wiring

harness.

Dispose of the old freeze

protecon thermostat properly.

Installing New Free Protecon

Thermostat

Locate the new freeze

protecon thermostat provided

in the kit.

To install freeze protecon

thermostat to outlet water

tube, gently push metal clamp onto

tubing. The metal clamp will snap into

place. Conrm thermostat sits ush

against piping. See Figure 18.

Connect freeze protecon

thermostat to the wiring

harness disconnected in Step 6 See

Figure 18.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 2.

Restore power to the water

heater. The water heater is now

ready for operaon.

SERVICE

Heater Block Upper

Wiring Assembly

Kit 100390080 Contains:

• Heater Block Upper Wiring

Assembly

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Mini Pick

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Removing the Heater Block

Upper Wiring Assembly

Locate the heater block upper

wiring harness. Reference

Figure 21 for locaon.

To disconnect, gently remove

the security clip with a mini

pick or ngernail. Push tab as shown

in Figure 19. Separate the harnesses.

Place security clip aside in a safe place

for reinstallaon.

White Wires

to Heater Blocks

Security

Clip

Lift

Here

White

Wire

Brown

Wire

Press

Tab

Figure 19 - Wiring security clip removal

Slide the heater cylinders A1

-A3 out from their exible

brackets. See Figure 21.

Remove the clip securing

heater block A4. See Figure 21.

Set the clip aside in a safe place for

reinstallaon.

Dispose of the old heater block

upper wiring assembly

properly.

Replacing the Heater Block

Upper Wiring Assembly

Locate the new heater block

upper wiring assembly

provided in the kit.

Install heater cylinders A1 - A2

as shown in Figure 21. The

heater cylinders are held in place by

exible brackets.

Use a Phillips screwdriver to

gently pry the exible brackets

away from the HEX to allow space for

the heater cylinders and wires to slide

out. Remove the two heater cylinders.

See Figure 20.

Pry

Bracket

Away From

HEX

Remove

Heater Cylinder

(right side)

Figure 20 - Heater Cylinder replacement

Heater cylinder A-3 is held in

place by a bracket with two

exible clips Reference Figure 3 for

placement and orientaon.

Heater block A4 uses a

compression style clip as

shown in Figure 21.

Reconnect the wiring harness

and security clip removed in

Step 5.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 2.

Restore power to the water

heater. The water heater is now

ready for operaon.

36 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Wiring Harness

Clip

Heater Cylinder

NOTICE: The heater cylinders

A1 - A3 t into the clips as

shown above.

Figure 21 - Upper connecon reference guide

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 37

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Heater Block Lower

Wiring Assembly

Kit 100390079 Contains:

• Heater Block Lower Wiring Assembly

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Mini Pick

• Bucket or Pan

• Towel or Rag

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Draining the Water Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three (3) screws

securing the X3®/Bypass

cartridge as shown in Figure 22.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 22 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 23 to

drain any residual water le in the

system. Place a bucket or pan

underneath inlet lter to collect water

during removal.

Inlet

Filter

Figure 23 - Removing the inlet lter

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Reinstall the cartridge to the

water heater. Locate the screws

previously removed in Step 5. Insert

and snug all three (3) screws by hand.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Use a screwdriver to ghten

the two

screws rst and

lastly ghten screw

. DO NOT use a

drill or impact driver to ghten the

screws.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon.

38 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Removing the Heater Block

Lower Wiring Assembly

Locate the heater block lower

wiring harness. Reference

Figure 6 on page 4 for locaon.

To disconnect, gently remove

the security clip with a mini

pick or ngernail. Push tab as shown

in Figure 24. Separate the harnesses.

Place security clip aside in a safe place

for reinstallaon.

White Wires

to Heater Blocks

Security

Clip

Lift

Here

White

Wire

Brown

Wire

Press

Tab

Figure 24 - Wiring security clip removal

Heater blocks B3 - B6 use a

compression style clip as shown

in Figure 27. Remove the compression

clips and set aside in a safe place for

reinstallaon.

Locate the C clip securing B2

heater block to the hot water

outlet piping. Remove the two screws

securing C clip. Place screws and C clip

aside in a safe place for reinstallaon.

See Figure 25.

Screws

C Clip

Thermistor

Heater Block

Outlet Tube

Figure 25 - Removing C clip and screws

CAUTION! Water may sll be

present in the valve assembly. Place a

rag under the valve connecon points

to prevent water from escaping into

the water heater cabinet.

Remove heater block B1 from

the inlet water connecon and

set aside for reinstallaon. See Figure

26.

Heater Block

Screw

Figure 26 - Heater block locaon

CAUTION! Water may sll be

present in the valve assembly. Place a

rag under the valve connecon points

to prevent water from escaping into

the water heater cabinet.

Dispose of the old heater block

lower wiring assembly properly.

Replacing the Heater Block

Lower Wiring Assembly

Locate the new heater block

lower wiring assembly provided

in the kit.

Reconnect heater blocks B3 -

B6 using the clips removed in

Step 16. Use Figure 27 for locaon

reference.

Reconnect heater block B2

using the C clip and screws

removed in Step 17. Use Figure 27 for

locaon reference.

Reconnect heater block B1

using the screws removed in

Step 18. Use Figure 27 for locaon

reference.

Reconnect heater block lower

wiring harness and security clip

removed in Step 15. Use Figure 27 for

locaon reference.

Reinstall the UIM using the four

screws removed in Step 13.

Checking for Water Leaks

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 11.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 39

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

B1 B2

Wiring Harness

Figure 27 - Lower connecon reference guide

40 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

THIS PAGE IS INTENTIONALLY LEFT BLANK

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 41

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Main Wiring Harness

Assembly

Kit 100390077 Contains:

• Main Wiring Harness

• Bypass Valve Extension Wire

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Mini Pick

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Accessing Water Heater

Components

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon.

NOTICE: UIM, bracket and wiring do

not need to be disconnected. Allow

UIM and bracket to rest below water

heater for easy access to the main

wiring harness.

Remove

4 screws

Figure 28 - Removing UIM and bracket screws

Removing the Main Wiring

Harness

NOTICE: Plasc clips secure the main

wiring harness at four locaons. Slide

the plasc clips towards the center

of the water heater to remove them.

They will stay with the harness.

Locate the exhaust thermistor

wiring harness and disconnect

it. See Figure 29.

Exhaust

Thermistor

Press

Figure 29 - Disconnecng exhaust thermistor

NOTICE: To disconnect the exhaust

thermistor, use a pair of needle

nose pliers to gently press down

on the connector tab while pulling

connecons apart.

Locate the high limit 1 wiring

harness and disconnect it. See

Figure 30.

High Limit 1

Disconnect

Figure 30 - Disconnecng high limit 1

Locate the high limit 2 wiring

harness and disconnect it. See

Figure 31.

High Limit 2

Disconnect

Figure 31 - Disconnecng high limit 2

Locate the ignitor assembly on

the right side of the water

heater. Remove the two screws

securing the ignitor assembly and

bracket to the gas manifold. Place

screws aside in a safe place for

reinstallaon. See Figure 32.

42 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Screws

Ignitor

Assembly

Ignitor

Wir e

Figure 32 - Ignitor assembly locaon

Disconnect the two spade

terminal connecons at the

back of ignitor assembly. See Figure

33.

Screw

Large Spade

Terminal

Small Spade

Terminal

Figure 33 - Disconnecng ignitor assembly

Locate the Printed Circuit Board

(PCB) on the right side of the

water heater. Use a Phillips

screwdriver to remove the two screws

securing the PCB. Place screws aside

in a safe place for reinstallaon. See

Figure 34.

Remove

2 screws

Printed Circuit Board

Figure 34 - Removing PCB screws

Gently slide PCB out from

water heater far enough to

access the wiring harnesses shown in

Figure 35.

Slide PCB Out

To Access

Figure 35 - Accessing PCB

Disconnect wiring harnesses

A1 - A4. See Figure 36.

PCB

Connection

Points

Figure 36 - Disconnecng wires A1-A4

NOTICE: On connecon points A1

& A4, use an O-ring pick to apply

pressure to the point shown in Figure

37 while pulling the harness from

the board. Remove "locks" and place

aside in a safe place for reinstallaon.

Gently

Twist

Pull

Wiring Harness

Lock

Figure 37 - Black harness lock removal

Locate the gas valve wiring

harness and disconnect it. See

Figure 38.

Locate the proporonal valve

wiring harness and disconnect

it. See Figure 38.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 43

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Gas Valve

Disconnect

Proportional

Valve

Figure 38 - Disconnecng gas valve and propor-

onal valve

Locate the inlet thermistor

wiring harness and disconnect

it. See Figure 39.

Disconnect

Inlet

Thermistor

Figure 39 - Disconnecng inlet thermistor

NOTICE: To disconnect the inlet

thermistor, use a pair of needle

nose pliers to gently press down

on the connector tab while pulling

connecons apart.

Locate the manifold wiring

harness and disconnect it. See

Figure 40.

Locate the ow wiring harness

and disconnect it. See Figure

40.

NOTICE: To disconnect the ow

thermistor, use a pair of needle

nose pliers to gently press down

on the connector tab while pulling

connecons apart.

Locate the outlet thermistor

wiring harness and disconnect

it. See Figure 40.

NOTICE: To disconnect the outlet

thermistor, use a pair of needle

nose pliers to gently press down

on the connector tab while pulling

connecons apart.

Disconnect

Flow

Outlet

Manifold

Figure 40 - Disconnecng manifold, ow &

outlet

Locate the liquid level wiring

harness and disconnect it. See

Figure 41.

Disconnect

Liquid Level

Figure 41 - Disconnecng liquid level

Locate the main water valve

wiring harness and disconnect

it. See Figure 42.

Disconnect

Main Water Valve

Figure 42 - Disconnecng main water valve

Locate the HEX thermistor

wiring harness and disconnect

it. See Figure 43.

Disconnect

HEX Thermistor

Figure 43 - Disconnecng HEX thermistor

NOTICE: To disconnect the HEX

thermistor, use a pair of needle

nose pliers to gently press down

on the connector tab while pulling

connecons apart.

44 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Locate the water valve 1 wiring

harness and extension wire

connected to the bypass valve.

Disconnect wiring at the bypass valve.

See Figure 44.

Disconnect

Water Valve 1

Extension Wire

Bypass Valve

Figure 44 - Disconnecng water valve 1 and

extension wire

Remove the main wiring

harness assembly with

extension wire and dispose of it

properly.

Replacing the Main Wiring

Harness

Locate the new main wiring

harness provided in the kit.

Reconnect the exhaust

thermistor harness removed in

Step 5.

Reconnect the high limit 1

harness removed in Step 6.

Reconnect the high limit 2

harness removed in Step 7.

Reconnect the ignitor assembly

wiring disconnected in Step 9.

Secure ignitor assembly to gas

manifold with the two screws

previously removed in Step 8.

Reconnect harnesses A1 - A4

removed from the PCB in

Step 12.

Reconnect the gas valve

harness removed in Step 13.

Reconnect the proporonal

valve harness removed in

Step 14.

Reconnect the inlet thermistor

valve harness removed in

Step 15.

Reconnect the manifold

harness removed in Step 16.

Reconnect the ow thermistor

harness removed in Step 17.

Reconnect the outlet

thermistor harness removed in

Step 18.

Reconnect the liquid level

harness removed in Step 19.

Reconnect the main water

valve harness removed in

Step 20.

Reconnect the HEX thermistor

harness removed in Step 21.

Locate the extension wire

provided in the kit. Connect the

blue end of extension wire to the

water valve 1 harness. Connect the

white end of extension wire to the

bypass valve previously disconnected

in Step 22.

With the wiring harnesses

secured, slide PCB back into

posion and secure PCB to mounng

brackets with the two screws

previously removed in Step 10.

Installing UIM and Bracket

Secure the User Interface

Module (UIM) and bracket to

water heater with the four screws

previously removed in Step 4. Conrm

all electrical connecons are snug and

properly routed behind bracket.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 2.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 45

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Freeze Protecon &

Power Wire Harness

Assembly

Kit 100390071 Contains:

• Freeze Protecon/Power Wire

Harness

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Cable Tie

• O-ring Pick

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Accessing Water Heater

Components

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Locate the Printed Circuit Board

(PCB) on the right side of the

water heater. Use a Phillips

screwdriver to remove the two screws

securing the PCB. Place screws aside

in a safe place for reinstallaon. See

Figure 45.

Remove

2 screws

Printed Circuit Board

Figure 45 - Removing PCB screws

Gently slide PCB out from

water heater enough to access

wiring harnesses A1 - A2. See Figure

46.

Replacing the Freeze

Protecon/Power Wire

Harness

Using Figure 46 as reference,

disconnect the wiring

harnesses A1 and A2 from the PCB.

PCB

Connection

Points

Figure 46 - Disconnecng PCB wiring

Most connecon points use a

simple, compression type

harness. Grasp each harness in the

middle and squeeze with a gentle pull

to disconnect them.

NOTICE: Wiring harness "A2"has

a plasc "lock" to ensure it does

not disconnect from the board.

Use the following steps to assist in

disconnecng this connecon.

On connecon point "A2", use

an O-ring pick to apply pressure

to the point shown in Figure 47 while

pulling the harness from the board.

Remove "lock" and place aside in a

safe place for reinstallaon.

Wiring

Harness

Lock

Gently

Twist

O-ring

Pick

Pull

Figure 47 - Red harness lock removal

Remove the cable e securing

the wiring harness to the UIM

bracket. See Figure 48.

Remove the screws securing

the two ground wires. Place the

screws aside in a safe place for

reinstallaon. See Figure 48.

Ground Wires

Cable Tie

Figure 48 - Ground wires and cable e removal.

Locate the 4 wiring harnesses

to the le of the UIM and

disconnect them. See Figure 49.

46 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Figure 49 - Wiring harness "B1-B4" locaon

Wiring harness connecons

B1 - B3 use a security clip.

Reference Figure 49 for locaon.

To disconnect wiring harnesses

B1 - B3, gently remove the

security clip with a mini pick or

ngernail. Push tab as shown in Figure

50. Separate the harnesses. Place

security clip aside in a safe place for

reinstallaon.

White Wires

to Heater Blocks

Security

Clip

Lift

Here

White

Wire

Brown

Wire

Press

Tab

Figure 50 - Wiring security clip removal

Disconnect wiring harness B4.

Reference Figure 49 for

locaon.

Disconnect wiring harness B5.

Reference Figure 51 for

locaon.

UIM Bracket

Figure 51 - Wiring harness "B5" locaon

Remove the old freeze

protecon/power wiring

harness and dispose of it properly.

Replacing the Freeze

Protecon/Power Harness.

Locate the new freeze

protecon/power wiring

harness provided in the kit.

Reconnect wiring harness B5

disconnected in Step 15.

Use a cable e to secure the

wiring harnesses to the UIM

removed in Step 9.

Reconnect the two ground

wires removed in Step 10.

Route wiring harnesses B1 - B4

behind the UIM bracket.

Reconnect wiring harness B4

disconnected in Step 14.

Reconnect wiring harnesses

B1 - B3 disconnected in

Step 13.

Route wiring harnesses A1 - A2

behind the gas valve to access

the PCB.

Reconnect the wiring harnesses

A1 - A2 to the PCB as removed

in Step 6.

With the wiring harnesses

secured, slide PCB back into

posion and secure PCB to mounng

brackets with the two screws

previously removed in Step 4.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 2.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 47

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Printed Circuit Board

Kit 100390074 Contains:

• Printed Circuit Board (TM-160)

• Kit Instrucons

Kit 100390073 Contains:

• Printed Circuit Board (TM-180)

• Kit Instrucons

Kit 100390072 Contains:

• Printed Circuit Board (TM-199)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• O-Ring Pick

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Accessing Water Heater

Components

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

IMPORTANT! Note the fan

designaon number provided on

the label located in the center of the

fan assembly. This fan designaon

number will be used later to properly

congure the water heater. See Figure

52.

Designation Number

Figure 52 - Fan designaon number

Removing the Printed Circuit

Board (PCB)

Locate the Printed Circuit Board

on the right side of the water

heater. Use a Phillips screwdriver to

remove the two screws securing the

PCB. Place screws aside in a safe place

for reinstallaon. See Figure 53.

Remove

2 screws

Printed Circuit Board

Figure 53 - Removing PCB screws

Gently slide PCB out from

water heater.

Using Figure 54 as reference,

disconnect the wiring

harnesses A through I from the PCB.

PCB

Connection

Points

Figure 54 - Disconnecng PCB wiring

48 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Most connecon points use a

simple, compression type

harness. Grasp each harness in the

middle and squeeze with a gentle pull

to disconnect them.

NOTICE: Wiring harnesses "B", "C",

and "H" have plasc "locks" to ensure

the harnesses do not disconnect

from the board. Use the following

steps to assist in disconnecng those

connecons.

On connecon point "B", use

an O-ring pick to apply pressure

to the point shown in Figure 55 while

pulling the harness from the board.

Remove "lock" and place aside in a

safe place for reinstallaon.

Wiring

Harness

Lock

Gently

Twist

O-ring

Pick

Pull

Figure 55 - Red harness lock removal

On connecon points "C" and

"H", use an O-ring pick to apply

pressure to the point shown in Figure

56 while pulling the harness from the

board. Remove "locks" and place

aside in a safe place for reinstallaon.

Gently

Twist

Pull

Wiring Harness

Lock

Figure 56 - Black harness lock removal

Connecon point "I" uses a

standard blade style connector.

Gently pull to remove.

Replacing the Printed Circuit

Board (PCB)

Locate the new PCB provided in

the kit.

Reconnect the wiring

harnesses removed in Steps

6-10. Reference Figure 54 for

placement of each wiring harness.

Reconnect the "locks" on wiring

harnesses "B", "C", and "H".

See Figure 55 and Figure 56 for

reference.

With the wiring harnesses

secured, slide PCB back into

posion and secure PCB to mounng

brackets with the two screws

previously removed in Step 4.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 2.

Restore power to the water

heater.

Conguring Water Heater

The water heater must be congured

to operate as intended with the new

PCB.

Use the tables and informaon found

in the "Conguraon Mode (C Mode)"

secon of this Service Handbook to

properly congure the system.

Congure water heater sengs

C01 (altude), C08 (vent size),

C02 (vent length) and lastly C04.

IMPORTANT! Conguraon sengs

must be done in the order described

above. See the "Conguraon Mode

(C Mode)" secon of this Service

Handbook for C01, C08 and C02

seng informaon.

Congure water heater seng

C04 to match the fan

designaon number on the fan

assembly recorded in Step 3. See

Figure 52 as reference.

The water heater is now ready for

operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 49

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Ignitor Assembly

Kit 100390067 Contains:

• Ignitor Assembly

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Accessing Water Heater

Components

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Removing the Ignitor Assembly

Screws

Ignitor

Assembly

Ignitor

Wir e

Figure 57 - Ignitor assembly locaon

Locate the ignitor assembly on

the right side of the water

heater. See Figure 57.

Disconnect the ignitor wire

from the ignitor assembly.

Remove the two screws

securing the ignitor assembly

and bracket to the gas manifold. Place

screws aside in a safe place for

reinstallaon. See Figure 57.

Disconnect the two spade

terminal connecons at the

back of ignitor and remove ignitor

assembly and bracket from water

heater. See Figure 58.

Locate the screw securing the

ignitor to the bracket. Remove

screw and place aside in a safe place

for reinstallaon. See Figure 58.

Screw

Large Spade

Terminal

Small Spade

Terminal

Figure 58 - Ignitor assembly locaon

Remove ignitor from bracket

and dispose of properly.

NOTICE: Do not dispose of bracket.

Bracket will be used to mount and

secure new ignitor.

Replacing the Ignitor Assembly

Locate the new ignitor

assembly provided in the kit.

Secure ignitor to bracket with screw

previously removed in Step 8.

Connect the two spade

terminal connecons to the

new ignitor assembly. Conrm

electrical connecons are ght.

NOTICE: There is one large and one

small spade terminal connecon.

Mount the new ignitor

assembly to the gas manifold

and secure with the two screws

previously removed in Step 6.

Reconnect the ignitor wire

previously removed in Step 5.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the two screws

previously removed in Step 2.

Restore power to the water

heater. The water heater is now

ready for operaon.

50 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Flame Sensor Wire

Kit 100390069 Contains:

• Flame Sensor Wire

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Accessing Water Heater

Components

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Replacing the Flame Sensor

Wire

Disconnect ame sensor wire

from ame sensor rod and the

Printed Circuit Board (PCB). Dispose of

properly. See Figure 59.

Plate

Flame

Sensor

Wire

Ignitor

Wire

Screws

(4x)

Figure 59 - Ignitor rod and ame sensor rod

assembly

NOTICE: If ame sensor wire is

dicult to disconnect from PCB,

remove the two screws securing PCB

to water heater. Gently slide PCB out

from water heater to improve access

to ame sensor connecon.

Locate new ame sensor wire

provided in the kit. Connect

new wire to ame sensor rod and

PCB. If PCB was removed for improved

access, gently slide PCB back into

place and secure with the two screws.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the two screws

previously removed in Step 2.

Restore power to water heater

and proceed.

The water heater is now ready for

operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 51

SERVICE (ELECTRONIC & WIRING COMPONENTS)

SERVICE

Exhaust and Water

Inlet Thermistor

Kit 100390060 Contains:

• Exhaust/Inlet Thermistor

• O-Ring (3.8 x 1.9 EPDM)

• Metal Clip

• Fan Clip

• Kit Instrucons

NOTICE: The fan clip is not used

to service this model and can be

discarded.

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• O-ring Pick

• Bucket or Pan (Inlet Thermistor)

• Towel or Rag

• Safety Gloves

WARNING!

This kit shall be installed

by a qualied service

agency in accordance

with the manufacturer’s

instructions and all

applicable codes

and requirements of

the authority having

jurisdiction. The

information in these

instructions must be

followed to minimize the

risk of re or explosion

or to prevent property

damage, personal

injury or death. The

qualied service agency

is responsible for the

proper installation of this

kit.

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

If replacing the exhaust

thermistor, shut OFF the gas

supply to the water heater at the

manual gas shut o valve.

If replacing the inlet thermistor,

shut OFF the cold water supply

to the water heater at the cold inlet

valve.

If replacing the inlet thermistor,

open all hot water xtures in

the house. When the residual water

ow has ceased, close all hot water

xtures. This will depressurize the

water heater.

IMPORTANT! If replacing the exhaust

thermistor, proceed to Step 12. If

replacing the inlet thermistor, proceed

to the next secon to drain the water

heater.

Draining the Water Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three screws

securing the X3®/Bypass

cartridge as shown in Figure 60.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 60 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 61 to

drain any residual water le in the

system. Place a bucket or pan

underneath inlet lter to collect water

during removal.

52 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (ELECTRONIC & WIRING COMPONENTS)

Inlet

Filter

Figure 61 - Removing the inlet lter

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Reinstall the cartridge to the

water heater. Locate the screws

previously removed in Step 6. Insert

and snug all three screws by hand.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Use a screwdriver to ghten

the two

screws rst and

lastly ghten screw

. DO NOT use a

drill or impact driver to ghten the

screws.

Accessing Water Heater

Components

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Thermistor Replacement

This kit can be used to replace the

following water thermistors:

• Exhaust - See Step 14.

• Water Inlet - See Step 22.

Removing the Exhaust

Thermistor

Locate the exhaust thermistor

as shown in Figure 62.

Exhaust

Thermistor

Wiring

Harness

Figure 62 - Exhaust thermistor locaon

Locate the screw securing the

exhaust thermistor. See Figure

63. Use a Phillips screwdriver to

remove the screw. Place the screw

aside in a safe place for reinstallaon.

Discard metal clip.

Thermistor

Metal Clip

Screw

Figure 63 - Exhaust thermistor removal

Disconnect the thermistor

wiring harness marked

"EXHAUST". See Figure 64.

NOTICE: To disconnect the exhaust

thermistor, use a pair of needle

nose pliers to gently press down

on the connector tab while pulling

connecons apart.

Wiring Harness

Press Here

Figure 64 - Wiring harness locaon

Use a mini pick or hook to

remove the thermistor O-ring

seated in the thermistor housing.

Dispose of the O-ring properly.

Dispose of the old exhaust

thermistor properly.

Replacing the Exhaust

Thermistor

Locate the new exhaust

thermistor, metal clip and

O-ring provided in the kit. Install

O-ring on the thermistor. See Figure

65.

O-ring

Thermistor

Figure 65 - New O-ring installaon

Install the new exhaust

thermistor in the water heater.

See Figure 63. Secure with the new

metal clip supplied in the kit and the

screw removed in Step 15.

Proceed to Step 33 to leak

check and return water heater

to operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 53

SERVICE

SERVICE (ELECTRONIC & WIRING COMPONENTS)

Removing the Water Inlet

Thermistor

Remove the four screws

securing the user interface

module (UIM) bracket. Place screws

aside in a safe place for reinstallaon.

NOTICE: UIM, bracket and wiring do

not need to be disconnected. Allow

UIM and bracket to rest below water

heater for easy access to the inlet

thermistor.

Locate the water inlet

thermistor as shown in Figure

66.

Inlet

Thermistor

Figure 66 - Water inlet thermistor locaon

Locate the screw securing

water inlet thermistor and clip

to the ow sensor as shown in Figure

67. Remove the screw and clip. Place

the screw aside in a safe place for

reinstallaon. Discard metal clip.

Thermistor

Metal Clip

Screw

Figure 67 - Water inlet thermistor removal

Disconnect the thermistor at

the wiring harness marked

"INLET" as shown in Figure 68.

Wiring Harness

Press Here

Figure 68 - Wiring harness removal

Remove the old water inlet

thermistor and dispose of it

properly.

Use a mini pick or hook to

remove the water inlet

thermistor O-ring seated in the ow

sensor. Dispose of the O-ring properly.

Replacing the Water Inlet

Thermistor

Locate the new thermistor,

metal clip, and O-ring provided

in the kit. Install the O-ring on the

thermistor. See Figure 69.

O-ring

Thermistor

Figure 69 - Thermistor O-ring installaon

Install the new water inlet

thermistor and O-ring in the

water heater. See Figure 67. Secure

with the new metal clip and the screw

removed in Step 24.

Connect the new thermistor

wiring harness to the harness

marked "INLET." See Figure 68.

Reinstall the user interface

module (UIM) bracket using the

four screws removed previously

removed in Step 22.

Proceed to Step 37 to leak

check the water and return

water heater to operaon.

Checking for Gas Leaks

IMPORTANT! DO NOT apply liquids

to any of the electrical connecons

when checking for gas leaks. Use a

towel or rag to protect any electrical

components.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve. Restore power to the

water heater. Open all hot water

xtures in the house. This will iniate

the call for heat at the water heater.

Use code approved methods to

check for leaks around all gas

connecon points. If any leaks are

detected, resecure components and

recheck for leaks.

Close all hot water xtures in

the house once the check is

complete.

Replace the cabinet cover and

secure with the screws

previously removed in Step 12.

The water heater is now ready for

operaon.

Checking for Water Leaks

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Replace the cabinet cover and

secure with the screws

previously removed in Step 12.

Restore power to the water

heater.

The water heater is now ready for

operaon.

54 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (ELECTRONIC & WIRING COMPONENTS)

Heat Exchanger

and Water Outlet

Thermistor

Kit 100371196 Contains:

• Water Thermistor

• O-ring (3.8 x 1.9 NBR)

• Metal Clip

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• O-ring Pick

• Bucket or Pan

• Towel or Rag

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Draining the Water Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three screws

securing the X3®/Bypass

cartridge as shown in Figure 70.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 70 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 71 to

drain any residual water le in the

system. Place a bucket or pan

underneath inlet lter to collect water

during removal.

Inlet

Filter

Figure 71 - Removing the inlet lter

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Reinstall the cartridge to the

water heater. Locate the screws

previously removed in Step 6. Insert

and snug all three screws by hand.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Use a screwdriver to ghten

the two

screws rst and

lastly ghten screw

. DO NOT use a

drill or impact driver to ghten the

screws.

Accessing Water Heater

Components

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Water Thermistor Replacement

This kit can be used to replace the

following water thermistors:

• Water Outlet - See Step 14.

• Heat Exchanger Outlet - See Step 21.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 55

SERVICE

SERVICE (ELECTRONIC & WIRING COMPONENTS)

Removing the Water Outlet

Thermistor

Locate the hot water outlet

thermistor and the two screws

securing the hot water outlet

thermistor. See Figure 72. Use a

Phillips screwdriver to remove the

screws and the C Clip. Place the

screws and C Clip aside in a safe place

for reinstallaon.

Screw

C Clip

Outlet Thermistor

Figure 72 - Outlet thermistor locaon

Disconnect the thermistor

wiring harness marked

"OUTLET". See Figure 73.

NOTICE: Press in the locaon shown

in Figure 4 to disconnect the wiring

harness.

Wiring Harness

Press Here

Figure 73 - Wiring harness locaon

Use a mini pick or hook to

remove the water inlet

thermistor O-ring seated in the water

outlet base. Dispose of the O-ring

properly.

Dispose of the old thermistor

properly.

Replacing the Water Outlet

Thermistor

Locate the new thermistor and

O-ring provided in the kit.

Install O-ring on the thermistor. See

Figure 74.

O-ring

Thermistor

Figure 74 - Thermistor O-ring locaon

Install the new water outlet

thermistor in the water heater.

See Figure 72. Secure with the screws

and C Clip removed in Step 14.

NOTICE: DO NOT use the metal clip

provided in the kit for this thermistor.

The metal clip may be discarded.

Proceed to Step 28 to leak

check the water and return

water heater to operaon.

Removing Heat Exchanger

Outlet Thermistor

Locate the heat exchanger

outlet thermistor as shown in

Figure 75.

Locate the screw securing the

heat exchanger outlet

thermistor. See Figure 75. Use a

Phillips screwdriver to remove the

screw and the metal clip. Remove

screw and place aside in a safe place

for reinstallaon. Discard metal clip.

Screw

Hex Thermistor

Metal Clip

Figure 75 - Outlet thermistor locaon

Disconnect the thermistor wiring

harness marked "HEX". See Figure 76.

NOTICE: Press in the locaon shown

in Figure 76 to disconnect the wiring

harness.

Wiring Harness

Press Here

Figure 76 - Wiring harness locaon

Use a mini pick or hook to

remove the heat exchanger

outlet thermistor O-ring seated in the

HEX outlet base. Dispose of the O-ring

properly.

Dispose of the old thermistor

properly.

56 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (ELECTRONIC & WIRING COMPONENTS)

Replacing Heat Exchanger

Outlet Thermistor

Locate the new thermistor,

O-ring and metal clip provided

in the kit. Install O-ring on the

thermistor. See Figure 77.

O-ring

Thermistor

Figure 77 - Thermistor O-ring locaon

Install the new heat exchanger

outlet thermistor in the water

heater. See Figure 75. Secure with the

new metal clip and the screw

removed in Step 22.

Proceed to Step 28 to leak

check the water and return

water heater to operaon.

Checking for Water Leaks

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 12.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 57

SERVICE

SERVICE (ELECTRONIC & WIRING COMPONENTS)

Gas Inlet Connector

Kit 100390061 Contains:

• Gas Inlet Connector

• (2x) O-Rings (25.7 x 3.5)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Bucket or Pan

• Towel or Rag

• Safety Gloves

WARNING!

This kit shall be installed

by a qualied service

agency in accordance

with the manufacturer’s

instructions and all

applicable codes

and requirements of

the authority having

jurisdiction. The

information in these

instructions must be

followed to minimize the

risk of re or explosion

or to prevent property

damage, personal

injury or death. The

qualied service agency

is responsible for the

proper installation of this

kit.

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Removing the Gas Inlet

Connector

Disconnect the gas line from

the gas inlet connector.

Locate the gas inlet connector

on the boom side of the

water heater. See Figure 78. Remove

the four screws securing the gas inlet

connector to the water heater

cabinet. Place screws aside in a safe

place for reinstallaon.

Screws

Figure 78 - Gas inlet connector locaon and

screws

Locate the set screw on the

boom ange of the gas valve.

Remove set screw and carefully

disconnect gas inlet connector from

gas valve. Place set screw aside in a

safe place for reinstallaon. See Figure

79.

Set

Screw

Figure 79 - Gas valve set screw

Replacing the Gas Inlet

Connector

Locate the two gas inlet

connector O-rings and new gas

inlet connector provided in the kit.

Install new O-rings to the new gas

inlet connector. See Figure 80.

NOTICE: Handle with care and verify

lubricant has been applied to O-ring

and O-ring is not dirty or damaged.

O-Rings

Figure 80 - Gas inlet connector O-rings

Install gas inlet connector to

gas valve and secure with set

screw previously removed in Step 7.

Secure gas inlet connector to

boom of water heater cabinet

with the four screws previously

removed in Step 6.

58 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Reconnect the gas line to the

gas inlet connector. Use an

approved thread sealant tape or pipe

dope when making the connecon.

Checking for Gas Leaks

Place a towel or rag around the

proporonal valve component

of the gas valve to keep it dry when

checking for leaks.

NOTICE: DO NOT apply liquids to any

of the electrical connecons when

checking for gas leaks.

Turn ON the gas supply to the

water heater at the manual gas

shuto valve.

Restore power to the water

heater.

Open all hot water xtures in

the house. This will iniate the

call for heat at the water heater.

Check for leaks around the base

of the gas valve and the gas

inlet connector. Use a small, so-

bristled brush to apply a hand

dishwashing soap and water mixture

(1 part soap to 15 parts water) or

children’s soap bubbles around the

gas valve connecons. If any leaks are

detected (which will appear as small

bubbles), resecure the connecons

and recheck for leaks.

Once no leaks have been

conrmed, remove towel or rag

from gas valve and electrical

connecons.

Close all hot water xtures in

the house once the check is

complete.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 3.

The water heater is now ready for

operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 59

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Gas Valve

Kit 100390062 Contains:

• Gas Valve

• (3x) O-rings (25.7 x 3.5)

• Gas Manifold Gasket

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Safety Gloves

WARNING!

This kit shall be installed

by a qualied service

agency in accordance

with the manufacturer’s

instructions and all

applicable codes

and requirements of

the authority having

jurisdiction. The

information in these

instructions must be

followed to minimize the

risk of re or explosion

or to prevent property

damage, personal

injury or death. The

qualied service agency

is responsible for the

proper installation of this

kit.

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Disconnecng Flame Sensor

Wire

Locate ame sensor wire

aached to burner assembly.

Disconnect wire and place aside for

easy access to the gas manifold. See

Figure 81.

Flame

Sensor

Wire

Burner Assembly

Figure 81 - Removing ame sensor wire

Disconnecng UIM and Bracket

Locate both green ground wires

aached to gas manifold cover.

Remove the two screws securing the

green ground wires and place them

aside in a safe place for reinstallaon.

See Figure 82.

Ground

Screw

Ground

Screw

Figure 82 - Removing green ground wires

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon. See Figure 83.

NOTICE: UIM, bracket and wiring do

not need to be disconnected. Allow

UIM and bracket to rest below water

heater.

Remove

4 screws

Figure 83 - Removing UIM and bracket screws

60 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Removing the Ignitor Assembly

Locate the ignitor assembly on

the right side of the water

heater. See Figure 84.

Disconnect the ignitor wire

from the ignitor assembly. See

Figure 84.

Remove the two screws

securing the ignitor assembly

and bracket to the gas manifold. Place

screws aside in a safe place for

reinstallaon. See Figure 84.

Screws

Ignitor

Assembly

Ignitor

Wir e

Figure 84 - Ignitor assembly locaon

Disconnect the two spade

terminal connecons at the

back of ignitor and remove ignitor

assembly and bracket from water

heater. See Figure 85.

Screw

Large Spade

Terminal

Small Spade

Terminal

Figure 85 - Disconnecng ignitor assembly

Removing Gas Manifold

Locate the gas manifold wire

harness and disconnect it. See

Figure 86.

Gas

Manifold

Wire

Figure 86 - Disconnecng gas manifold wire

Locate and remove the four

screws securing the gas valve to

the gas manifold. Place screws aside

in a safe place for reinstallaon. See

Figure 87.

Screws (4)

Inlet

Manifold

Figure 87 - Remove gas valve screws

Locate the eight screws

securing the gas manifold to

the burner assembly. Remove screws

and place aside in a safe place for

reinstallaon. See Figure 88.

Gas

Manifold

Screws (8x)

Figure 88 - Removing gas manifold screws

Remove the manifold and place

aside for reinstallaon.

Removing the Gas Valve

Locate the gas valve at the

boom right side of the water

heater. See Figure 89.

Screws (4)

Set

Screw

Gas Valve

Wiring

Harness

Clear

Gas

Tube

Figure 89 - Gas valve locaon and connecons

Remove the clear gas tube from

the gas valve and place aside.

See Figure 87.

Disconnect the two wire

harnesses connected to the gas

valve. See Figure 87. The wires are

labeled:

• "Gas Valve"

• "Proporonal Valve"

Wiring Harnesses

Clear Gas

Tube

Figure 90 - Gas tube and wire harnesses

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 61

SERVICE

SERVICE (COMBUSTION COMPONENTS)

62 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (COMBUSTION COMPONENTS)

Locate the set screw on the

boom ange of the gas valve.

Remove set screw and place aside in a

safe place for reinstallaon. See Figure

91.

Set

Screw

Figure 91 - Gas valve set screw

Remove old gas valve and

dispose of properly.

Replacing the Gas Valve

Locate the new gas valve and

gas valve O-rings (3x) provided

in the kit. Install one new O-ring to gas

valve as shown in Figure 92.

NOTICE: Handle with care and verify

lubricant has been applied to O-ring

and O-ring is not dirty or damaged.

O-Ring

Figure 92 - O-ring replacement (one O-ring)

Locate the gas connector

O-rings and remove them.

Install two new O-rings to gas

connector. See Figure 93.

NOTICE: Handle with care and verify

lubricant has been applied to O-ring

and O-ring is not dirty or damaged.

O-Rings

Figure 93 - Gas connector O-rings

Before installing new gas valve

to water heater, verify rubber

boot is properly inserted into boom

of water heater cabinet as shown in

Figure 94.

NOTICE: The proporonal valve

component of the gas valve will rest

on top of this rubber boot.

Rubber

Boot

Figure 94 - Verify rubber boot placement

Connect the clear gas tube to

the new gas valve previously

disconnected in Step 17.

Connect the two wiring

harnesses to the new gas valve

previously disconnected in Step 18.

Secure gas valve using the set

screw previously removed in

Step 19.

Installing Gas Manifold

Locate the gas manifold gasket

provided in the kit. Use a

plasc scraper to gently scrape old

insulaon gasket clean from gas

manifold. Conrm assembly surface is

free of any debris or leover

insulaon. Install new gasket to gas

manifold. See Figure 95.

IMPORTANT! DO NOT gouge or

damage assembly surface when

removing insulaon gasket.

NOTICE: Handle with care and verify

gasket is not dirty or damaged.

Gas Manifold Gasket

Figure 95 - Replacing gas manifold gasket

Reinstall the gas manifold to

the burner assembly using the

eight screws previously removed in

Step 14.

NOTICE: Inspect burner assembly

surface for debris and clean surface if

necessary. Conrm new gas manifold

gasket is free of debris before

installing to burner assembly.

Locate the four screws

previously removed in Step 13,

and secure the gas manifold to the gas

valve. See Figure 87.

SERVICE

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 63

SERVICE (COMBUSTION COMPONENTS)

Installing the Ignitor Assembly

Locate the ignitor assembly.

Connect the two spade

terminal connecons to the ignitor

assembly. Conrm electrical

connecons are ght.

NOTICE: There is one large and one

small spade terminal connecon.

Mount the ignitor assembly to

the gas manifold and secure

with the two screws previously

removed in Step 10.

Reconnect the ignitor wire

previously removed in Step 9.

Installing UIM and Bracket

Secure the User Interface

Module (UIM) and bracket to

water heater with the four screws

previously removed in Step 7. Conrm

all electrical connecons are snug and

properly routed behind bracket.

Connecng Flame Sensor Wire

Locate the ame sensor

previously disconnected from

burner assembly in Step 5. Connect

ame sensor wire. See Figure 81.

Checking for Gas Leaks

IMPORTANT! DO NOT apply liquids

to any of the electrical connecons

when checking for gas leaks. Use a

towel or rag to protect any electrical

components.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve. Restore power to the

water heater. Open all hot water

xtures in the house. This will iniate

the call for heat at the water heater.

Use code approved methods to

check for leaks around all gas

connecon points. If any leaks are

detected, resecure components and

recheck for leaks.

Close all hot water xtures in

the house once the check is

complete.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the two screws

previously removed in Step 3.

The water heater is now ready

for operaon.

SERVICE

Fan Assembly

Kit 100390065 Contains:

• Fan Assembly

• Rubber Stopper

• Metal Clip

• O-Ring (3.8 x 1.9)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• 12" Magnezed Phillips Screwdriver

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Draining the Water Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three (3) screws

securing the X3®/Bypass

cartridge as shown in Figure 96.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 96 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 97 to

drain any residual water le in the

system. Place a bucket or pan

underneath inlet lter to collect water

during removal.

Inlet

Filter

Figure 97 - Removing the inlet lter

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Reinstall the cartridge to the

water heater. Locate the screws

previously removed in Step 6. Insert

and snug all three (3) screws by hand.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Use a screwdriver to ghten

the two

screws rst and

lastly ghten screw

. DO NOT use a

drill or impact driver to ghten the

screws.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Disconnecng UIM and Bracket

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon. See Figure 98.

NOTICE: UIM, bracket and wiring

do not need to be disconnected.

Allow UIM and bracket to rest below

water heater for easy access to fan

assembly.

64 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (COMBUSTION COMPONENTS)

SERVICE

Remove

4 screws

Figure 98 - Removing UIM and bracket screws

Disconnecng Flow Control

Valve

Locate the ow control valve in

the water heater as shown in

Figure 99.

NOTICE: Some components and wiring

have been removed for clarity.

Spring Clip

Flow Control Valve

Figure 99 - Locang and disconnecng ow

control valve

CAUTION! Water may sll be

present in the valve assembly. Place a

rag under the valve connecon points

to prevent water from escaping into

the water heater cabinet.

Remove the two spring clips

(size 25) securing the ow

control valve to the piping system.

Place the spring clips aside in a safe

place for reinstallaon. See Figure 99.

Remove the ow control valve

from the piping system and

allow it to rest near the boom of the

water heater for easy access to fan

assembly.

Disconnecng Fan Assembly

from Printed Circuit Board

(PCB)

Locate the Printed Circuit Board

(PCB) on the right side of the

water heater. Use a Phillips

screwdriver to remove the two screws

securing the PCB. Place screws aside

in a safe place for reinstallaon. See

Figure 100.

Remove

2 screws

Printed Circuit Board

Figure 100 - Removing PCB screws

Gently slide PCB out from

water heater.

Using Figure 101 as reference,

disconnect the fan assembly

wiring harness from PCB.

Fan Assembly

Connection

Point

Figure 101 - Disconnecng fan assembly from

PCB

Removing Fan Assembly

Locate the ve screws securing

the fan assembly to the burner.

There are two screws securing the

front of the fan assembly (A), two

screws securing the back of the fan

assembly (B), and one screw securing

the fan bracket (C) to the water heater

cabinet. See Figure 102 & Figure 103.

Remove 2 (A) screws

Remove 2 (B) screws

Fan

Assembly

Figure 102 - Fan screw locaon (A & B)

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 65

SERVICE (COMBUSTION COMPONENTS)

SERVICE

Remove

1 (C) screw

Fan

Assembly

Figure 103 - Fan screw locaon (C)

Remove all screws and place

them aside in a safe place for

reinstallaon.

Remove fan assembly from

burner. Rotate fan assembly

90° counterclockwise and remove fan

assembly from water heater.

NOTICE: For easy removal, guide the

fan around the le side of the inlet

manifold as shown in Figure 104.

Rotate &

Remove

Fan

Assembly

Figure 104 - Rotate and remove fan assembly

Preparing New Fan Assembly

Locate the new fan assembly

provided in the kit.

IMPORTANT! Note the fan

designaon number provided on the

label located in the center of both

the old and new fan assemblies.

This informaon will be used later to

properly congure the water heater.

See Figure 105.

Designation Number

Figure 105 - Fan designaon number

Remove the three screws

securing the fan bracket to the

old fan assembly. Place screws aside

in a safe place for reinstallaon. See

Figure 106.

Fan Bracket

Install

3 screws

Figure 106 - Install fan bracket

Secure the new fan bracket to

the new fan assembly using the

screws removed Step 25. See Figure

106.

Remove the screw securing the

metal clip and stopper to the

old fan assembly. Place screw in a safe

place for reinstallaon. See Figure

107.

Screw

Metal

Clip

Stopper

Figure 107 - Stopper installaon

Using the new metal clip,

secure the new stopper to the

new fan assembly with the screw

removed in Step 27. See Figure 107.

Dispose of old fan assembly properly.

Installing New Fan Assembly

Rotate new fan assembly 90°

counterclockwise so the fan

outlet is facing the water heater.

Insert fan assembly into water heater

using the same method as outlined in

Step 23 in reverse order. See Figure

104.

Install fan assembly outlet

rmly into burner. Verify all

screw hole locaons align properly.

Secure fan assembly with the ve

screws previously removed in Step 22,

starng with the bracket screw (C) to

help stabilize the fan assembly.

Guide fan assembly wiring

harness behind gas valve. Using

Figure 101 as reference, connect fan

assembly wiring harness to PCB.

NOTICE: The O-ring is not used

to service this model and can be

discarded.

66 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Installing Printed Circuit Board

(PCB)

With the fan assembly wiring

harness secured, slide PCB back

into posion and secure PCB to

mounng brackets with the two

screws previously removed in Step 18.

Installing Flow Control Valve

Carefully install ow control

valve to pipe connecons.

Conrm wiring connecons are

secure.

Locate the two (2) spring clips

previously removed in Step 16.

Install spring clips to ow control

valve, securing it to piping

connecons. See Figure 99. Verify

water connecons are ght and will

not leak.

Installing UIM and Bracket

Secure the User Interface

Module (UIM) and bracket to

water heater with the four screws

previously removed in Step 14.

Conrm all electrical connecons are

snug and properly routed behind

bracket.

Checking for Water Leaks

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 12.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater.

If the old fan designaon

number recorded in Step 24

matches the new fan designaon

number, the water heater is now

ready for operaon.

Proceed to the following secon to

congure water heater for new fan

designaon number.

Conguring Water Heater for

New Fan Designaon Number

Your water heater must be congured

to operate as intended with the new

fan assembly. Follow the procedure

below to access C Mode at the UIM

and properly congure water heater.

Press and hold the "UP" buon

and the "SETTING" buon for 5

seconds to access C Mode.

Press the "UP" buon or the

"DOWN" buon to search for C

code C04.

Press the "SETTING" buon

and adjust the value of C04

using the "UP" and "DOWN" buons

to match the fan designaon number

on the new fan assembly recorded in

Step 24. See Figure 105 as reference.

The value will ash.

Press the "SETTING" buon

again to conrm the new value

selected is correct.

Press and hold the "UP" buon

and the "DOWN" buon for 5

seconds to return the display to

normal operaon.

To cycle power, disconnect

power to the water heater by

unplugging it or by turning o the

circuit at the breaker box, as

appropriate.

Restore power and press the

"POWER" buon to turn the

water heater on again.

The water heater is now ready for

operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 67

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Gas Manifold

Kit 100390063 Contains:

• Gas Manifold

• Gas Valve O-ring (25.7 x 3.5)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• 12" Magnezed Phillips Screwdriver

• Safety Gloves

WARNING!

This kit shall be installed

by a qualied service

agency in accordance

with the manufacturer’s

instructions and all

applicable codes

and requirements of

the authority having

jurisdiction. The

information in these

instructions must be

followed to minimize the

risk of re or explosion

or to prevent property

damage, personal

injury or death. The

qualied service agency

is responsible for the

proper installation of this

kit.

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Disconnecng Flame Sensor

Wire

Locate ame sensor wire

aached to burner assembly.

Disconnect wire and place aside for

easy access to the gas manifold. See

Figure 108.

Flame

Sensor

Wire

Burner Assembly

Figure 108 - Removing ame sensor wire

Disconnecng UIM and Bracket

Locate both green ground wires

aached to gas manifold cover.

Remove the two screws securing the

green ground wires and place them

aside in a safe place for reinstallaon.

See Figure 109.

Ground

Screw

Ground

Screw

Figure 109 - Removing green ground wires

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon. See Figure 110.

NOTICE: UIM, bracket and wiring do

not need to be disconnected. Allow

UIM and bracket to rest below water

heater for easy access to gas manifold.

Remove

4 screws

Figure 110 - Removing UIM and bracket screws

68 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Removing the Ignitor Assembly

Locate the ignitor assembly on

the right side of the water

heater. See Figure 111.

Disconnect the ignitor wire

from the ignitor assembly. See

Figure 111.

Remove the two screws

securing the ignitor assembly

and bracket to the gas manifold. Place

screws aside in a safe place for

reinstallaon. See Figure 111.

Screws

Ignitor

Assembly

Ignitor

Wir e

Figure 111 - Ignitor assembly locaon

Disconnect the two spade

terminal connecons at the

back of ignitor and remove ignitor

assembly and bracket from water

heater. See Figure 112.

Screw

Large Spade

Terminal

Small Spade

Terminal

Figure 112 - Disconnecng ignitor assembly

Removing Gas Manifold

Locate the gas manifold wire

harness and disconnect it. See

Figure 113.

Gas

Manifold

Wire

Figure 113 - Disconnecng gas manifold wire

Locate and remove the four

screws securing the gas valve to

the gas manifold. Place screws aside

in a safe place for reinstallaon. See

Figure 114.

Screws (4)

Inlet

Manifold

Figure 114 - Remove gas valve screws

Locate the eight screws

securing the gas manifold to

the burner assembly. Remove screws

and place aside in a safe place for

reinstallaon. See Figure 115.

Gas

Manifold

Screws (8x)

Figure 115 - Removing gas manifold screws

Remove gas manifold and

dispose of properly.

Installing New Gas Manifold

Locate the gas valve O-ring

(25.7 x 3.5) provided in the kit.

Remove the old O-ring from gas valve

and install new O-ring as shown in

Figure 116.

NOTICE: Handle with care and verify

lubricant has been applied to O-ring

and O-ring is not dirty or damaged.

O-Ring

Figure 116 - O-ring replacement

Locate new gas manifold

provided in the kit and install it

to burner assembly using the eight

screws previously removed in Step 14.

NOTICE: Inspect burner assembly

surface for debris and clean surface if

necessary. Conrm new gas manifold

gasket is free of debris before

installing to burner assembly.

Locate the four screws

previously removed in Step 13

and secure the gas manifold to the gas

valve. Figure 114.

Locate the gas manifold wire

harness and connect it. See

Figure 113.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 69

SERVICE

SERVICE (COMBUSTION COMPONENTS)

70 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Installing the Ignitor Assembly

Locate the ignitor assembly.

Connect the two spade

terminal connecons to the ignitor

assembly. Conrm electrical

connecons are ght.

NOTICE: There is one large and one

small spade terminal connecon.

Mount the ignitor assembly to

the gas manifold and secure

with the two screws previously

removed in Step 10.

Reconnect the ignitor wire

previously removed in Step 9.

Installing UIM and Bracket

Secure the User Interface

Module (UIM) and bracket to

water heater with the four screws

previously removed in Step 7. Conrm

all electrical connecons are snug and

properly routed behind bracket.

Connecng Flame Sensor Wire

Locate the ame sensor

previously disconnected from

burner assembly in Step 5. Connect

ame sensor wire. See Figure 108.

Checking for Gas Leaks

IMPORTANT! DO NOT apply liquids

to any of the electrical connecons

when checking for gas leaks. Use a

towel or rag to protect any electrical

components.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve. Restore power to the

water heater. Open all hot water

xtures in the house. This will iniate

the call for heat at the water heater.

Use code approved methods to

check for leaks around all gas

connecon points. If any leaks are

detected, resecure components and

recheck for leaks.

Close all hot water xtures in

the house once the check is

complete.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the two screws

previously removed in Step 3.

The water heater is now ready

for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 71

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Ignitor Rod & Flame

Sensor Rod Assembly

Kit 100390068 Contains:

• Ignitor Rod and Flame Sensor Rod

Assembly

• Gasket

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Safety Gloves

WARNING!

This kit shall be installed

by a qualied service

agency in accordance

with the manufacturer’s

instructions and all

applicable codes

and requirements of

the authority having

jurisdiction. The

information in these

instructions must be

followed to minimize the

risk of re or explosion

or to prevent property

damage, personal

injury or death. The

qualied service agency

is responsible for the

proper installation of this

kit.

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Accessing Water Heater

Components

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Removing the Ignitor Rod and

Flame Sensor Rod Assembly

Disconnect ame sensor wire

from the assembly. See Figure

117.

Plate

Flame

Sensor

Wire

Ignitor

Wire

Screws

(4x)

Figure 117 - Ignitor rod and ame sensor rod

assembly

Disconnect ignitor wire from

ignitor assembly. See Figure

118.

Ignitor

Wire

Ignitor

Assembly

Figure 118 - Disconnecng ignitor wire

Locate the four screws securing

the plate to the burner

assembly. Remove the screws and

place them aside in a safe place for

reinstallaon. See Figure 118.

Remove the ignitor rod and

ame sensor rod assembly

from the burner assembly and dispose

of properly.

Use a plasc scraper to gently

scrape old insulaon gasket

clean from burner assembly. Conrm

burner assembly surface is free of any

debris or leover insulaon.

IMPORTANT! DO NOT gouge or

damage burner assembly surface

when removing insulaon gasket.

Installing New Ignitor Rod and

Flame Sensor Rod Assembly

Locate new ignitor rod and

ame sensor rod assembly

provided in kit. Locate gasket provided

in kit. Place gasket on back side of

ignitor rod and ame sensor rod

assembly. Conrm screw hole

locaons align.

Locate the four screws

previously removed in Step 7.

Secure the ignitor rod and ame

sensor rod assembly to the burner

assembly with the four screws.

Reconnect the ame sensor

wire and ignitor wire previously

removed in Steps 5 & 6.

Checking for Gas Leaks

IMPORTANT! DO NOT apply liquids

to any of the electrical connecons

when checking for gas leaks. Use a

towel or rag to protect any electrical

components.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve. Restore power to the

water heater. Open all hot water

xtures in the house. This will iniate

the call for heat at the water heater.

Use code approved methods to

check for leaks around all gas

connecon points and the ignitor rod

and ame sensor rod assembly. If any

leaks are detected, resecure

components and recheck for leaks.

Once no leaks have been

conrmed, remove towel or rag

from electrical connecons if

necessary.

Close all hot water xtures in

the house once the check is

complete. Proceed to the next

secon.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the two screws

previously removed in Step 3.

The water heater is now ready

for operaon.

72 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Burner Assembly

Kit 100390064 Contains:

• Burner Assembly

• Gas Manifold Gasket

• Gas Valve O-ring (size 25.7 x 3.5)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• 12" Magnezed Phillips Screwdriver

• Safety Gloves

WARNING!

This kit shall be installed

by a qualied service

agency in accordance

with the manufacturer’s

instructions and all

applicable codes

and requirements of

the authority having

jurisdiction. The

information in these

instructions must be

followed to minimize the

risk of re or explosion

or to prevent property

damage, personal

injury or death. The

qualied service agency

is responsible for the

proper installation of this

kit.

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Disconnecng Flame Sensor

Wire

Locate ame sensor wire

aached to burner assembly.

Disconnect wire and place aside for

easy access to the gas manifold. See

Figure 119.

Flame

Sensor

Wire

Burner Assembly

Figure 119 - Removing ame sensor wire

Disconnecng UIM and Bracket

Locate both green ground wires

aached to gas manifold cover.

Remove the two screws securing the

green ground wires and place them

aside in a safe place for reinstallaon.

See Figure 120.

Ground

Screw

Ground

Screw

Figure 120 - Removing green ground wires

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon. See Figure 121.

NOTICE: UIM, bracket and wiring do

not need to be disconnected. Allow

UIM and bracket to rest below water

heater for easy access to gas manifold.

Remove

4 screws

Figure 121 - Removing UIM and bracket screws

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 73

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Removing the Ignitor Assembly

Locate the ignitor assembly on

the right side of the water

heater. See Figure 122.

Disconnect the ignitor wire

from the ignitor assembly. See

Figure 122.

Remove the two screws

securing the ignitor assembly

and bracket to the gas manifold. Place

screws aside in a safe place for

reinstallaon. See Figure 122.

Screws

Ignitor

Assembly

Ignitor

Wir e

Figure 122 - Ignitor assembly locaon

Disconnect the two spade

terminal connecons at the

back of ignitor and remove ignitor

assembly and bracket from water

heater. See Figure 123.

Screw

Large Spade

Terminal

Small Spade

Terminal

Figure 123 - Disconnecng ignitor assembly

Removing Gas Manifold

Locate the gas manifold wire

harness and disconnect it. See

Figure 124.

Gas

Manifold

Wire

Figure 124 - Disconnecng gas manifold wire

Locate and remove the four

screws securing the gas valve

to the gas manifold. Place screws

aside in a safe place for reinstallaon.

See Figure 125.

Screws (4)

Inlet

Manifold

Figure 125 - Remove gas valve screws

Locate the eight screws

securing the gas manifold to

the burner assembly. Remove screws

and place aside in a safe place for

reinstallaon. See Figure 126.

Gas

Manifold

Screws (8x)

Figure 126 - Removing gas manifold screws

Remove gas manifold and place

it aside in a safe place for

reinstallaon.

Removing Burner Assembly

Locate the overheat cuto fuse

(OHCF) above the burner

assembly. Remove the two guide clips

from the burner assembly roung the

OHCF around the primary heat

exchanger. See Figure 127.

Locate the two boom screws

securing the burner assembly

to the water heater as shown in Figure

127. Use a 12" magnezed Phillips

screwdriver to remove screws. Place

screws aside in a safe place for

reinstallaon.

Locate the nine top screws

securing the burner assembly

to the water heater as shown in Figure

127. Use a 12" magnezed Phillips

screwdriver to remove screws. Place

screws aside in a safe place for

reinstallaon.

Top Burner Screws (9x)

Bottom Burner

Screws (2x)

Guide Clips

Figure 127 - Burner screws and guide clips

Remove burner assembly from

water heater and dispose of

properly.

74 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Installing New Burner

Assembly

Locate the new burner

assembly provided in the kit.

Install burner assembly to water

heater with the nine top screws

previously removed in Step 18.

Locate the two boom screws

previously removed in Step 17

and secure boom of burner

assembly to water heater.

Install the OHCF guide clips to

burner assembly previously

removed in Step 16.

Installing Gas Manifold

Locate the gas manifold gasket

provided in the kit. Use a

plasc scraper to gently scrape old

insulaon gasket clean from gas

manifold. Conrm assembly surface is

free of any debris or leover

insulaon. Install new gasket to gas

manifold. See Figure 128.

IMPORTANT! DO NOT gouge or

damage assembly surface when

removing insulaon gasket.

NOTICE: Handle with care and verify

gasket is not dirty or damaged.

Gas Manifold Gasket

Figure 128 - Replacing gas manifold gasket

Locate the new gas valve O-ring

provided in the kit. Install

O-ring to gas valve as shown in Figure

129.

NOTICE: Handle with care and verify

lubricant has been applied to O-ring

and O-ring is not dirty or damaged.

O-Ring

Figure 129 - O-ring replacement (one O-ring)

Install gas manifold to burner

assembly using the eight

screws previously removed in Step 14.

NOTICE: Inspect new burner assembly

surface for debris and clean surface if

necessary. Conrm new gas manifold

gasket is free of debris before

installing to burner assembly.

Locate the four screws

previously removed in Step 13

and secure the gas manifold to the gas

valve. See Figure 125.

Locate the gas manifold wire

harness and connect it. See

Figure 124.

Installing the Ignitor Assembly

Locate the ignitor assembly.

Connect the two spade

terminal connecons to the ignitor

assembly. Conrm electrical

connecons are ght.

NOTICE: There is one large and one

small spade terminal connecon.

Mount the ignitor assembly to

the gas manifold and secure

with the two screws previously

removed in Step 10.

Reconnect the ignitor wire

previously removed in Step 9.

Installing UIM and Bracket

Secure the User Interface

Module (UIM) and bracket to

water heater with the four screws

previously removed in Step 7. Conrm

all electrical connecons are snug and

properly routed behind bracket.

Connecng Flame Sensor Wire

Locate the ame sensor

previously disconnected from

burner assembly in Step 5. Connect

ame sensor wire. See Figure 119.

Checking for Gas Leaks

IMPORTANT! DO NOT apply liquids

to any of the electrical connecons

when checking for gas leaks. Use a

towel or rag to protect any electrical

components.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve. Restore power to the

water heater. Open all hot water

xtures in the house. This will iniate

the call for heat at the water heater.

Use code approved methods to

check for leaks around all gas

connecon points. If any leaks are

detected, resecure components and

recheck for leaks.

Close all hot water xtures in

the house once the check is

complete.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the two screws

previously removed in Step 3.

The water heater is now ready

for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 75

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Primary & Secondary

Heat Exchangers (HEX),

OHCF Wire

Kit 100390054 Contains:

• Primary HEX Assembly

• (4x) O-ring (15.5 x 2.5)

• Gas Manifold Gasket

• Burner Assembly Gasket

• Kit Instrucons

Kit 100390052 Contains:

• Secondary HEX Assembly

• (4x) O-ring (15.5 x 2.5)

• HEX Gasket

• Kit Instrucons

Kit 100390055 Contains:

• Overheat Cuto Fuse (OHCF) Wire

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• 12" Magnezed Phillips Screwdriver

• Bucket or Pan

• Towel or Rag

• Safety Gloves

WARNING!

This kit shall be installed

by a qualied service

agency in accordance

with the manufacturer’s

instructions and all

applicable codes

and requirements of

the authority having

jurisdiction. The

information in these

instructions must be

followed to minimize the

risk of re or explosion

or to prevent property

damage, personal

injury or death. The

qualied service agency

is responsible for the

proper installation of this

kit.

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Draining the Water Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three (3) screws

securing the X3®/Bypass

cartridge as shown in Figure 130.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 130 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 131 to

drain any residual water le in the

system. Place a bucket or pan

underneath inlet lter to collect water

during removal.

Inlet

Filter

Figure 131 - Removing the inlet lter

76 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Reinstall the cartridge to the

water heater. Locate the screws

previously removed in Step 6. Insert

and snug all three (3) screws by hand.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Use a screwdriver to ghten

the two

screws rst and

lastly ghten screw

. DO NOT use a

drill or impact driver to ghten the

screws.

Locate the heat exchanger

(HEX) drain line underneath the

water heater. See Figure 132. Remove

the two screws securing the metal

bracket and place them aside in a safe

place for reinstallaon.

Bracket

Screws

Plug

Figure 132 - HEX drain assembly

Remove the HEX drain plug by

twisng and pulling down. Set

the plug aside in a safe place for

reinstallaon.

Once the HEX drain line has

been adequately drained,

reinstall it. Conrm HEX drain plug is

secured and reinstall the bracket using

the two (2) screws removed in Step

12.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Disconnecng Flame Sensor

Wire

Locate ame sensor wire

aached to burner assembly.

Disconnect wire and place aside for

easy access to the gas manifold. See

Figure 133.

Plate

Flame

Sensor

Wire

Ignitor

Wire

Screws

(4x)

Figure 133 - Removing ame sensor wire

Disconnecng UIM and Bracket

Locate both green ground wires

aached to gas manifold cover.

Remove the two screws securing the

green ground wires and place them

aside in a safe place for reinstallaon.

See Figure 134.

Ground

Screw

Ground

Screw

Figure 134 - Removing green ground wires

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon. See Figure 135.

NOTICE: UIM, bracket and wiring do

not need to be disconnected. Allow

UIM and bracket to rest below water

heater for easier access.

Remove

4 screws

Figure 135 - Removing UIM and bracket screws

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 77

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Removing the Ignitor Assembly

Locate the ignitor assembly on

the right side of the water

heater. See Figure 136.

Disconnect the ignitor wire

from the ignitor assembly. See

Figure 136.

Remove the two screws

securing the ignitor assembly

and bracket to the gas manifold. Place

screws aside in a safe place for

reinstallaon. See Figure 136.

Screws

Ignitor

Assembly

Ignitor

Wir e

Figure 136 - Ignitor assembly locaon

Disconnect the two spade

terminal connecons at the

back of ignitor and remove ignitor

assembly and bracket from water

heater. See Figure 137.

Screw

Large Spade

Terminal

Small Spade

Terminal

Figure 137 - Disconnecng ignitor assembly

wires

Disconnecng Flow Control

Valve

Locate the ow control valve in

the water heater as shown in

Figure 138.

NOTICE: Some components and

wiring have been removed for clarity.

Spring Clip

Flow Control Valve

Figure 138 - Locang and disconnecng ow

control valve

CAUTION! Water may sll be

present in the valve assembly. Place a

rag under the valve connecon points

to prevent water from escaping into

the water heater cabinet.

Remove the two spring clips

(size 25) securing the ow

control valve to the piping system.

Place the spring clips aside in a safe

place for reinstallaon. See Figure

138.

Remove the ow control valve

from the piping system and

allow it to rest near the boom of the

water heater for easier access.

Disconnecng Gas Manifold

Wire Harness

Locate the gas manifold wire

harness and disconnect it. See

Figure 139.

Gas

Manifold

Wire

Figure 139 - Disconnecng gas manifold wire

Disconnecng Overheat Cuto

Fuse (OHCF) Wire

Locate the OHCF wire and

disconnect it. See Figure 140.

OHCF Wire

Disconnect

Wire Harness

Figure 140 - Disconnecng OHCF wire

Removing Fan Assembly

Locate the ve screws securing

the fan assembly to the burner.

There are two screws securing the

front of the fan assembly (A), two

screws securing the back of the fan

assembly (B), and one screw securing

the fan bracket (C) to the water heater

cabinet. See Figure 141 & Figure 142.

Remove 2 (A) screws

Remove 2 (B) screws

Fan

Assembly

Figure 141 - Fan screw locaon (A & B)

78 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (COMBUSTION COMPONENTS)

SERVICE

Remove

1 (C) screw

Fan

Assembly

Figure 142 - Fan screw locaon (C)

Remove all screws and place

them aside in a safe place for

reinstallaon.

Remove fan assembly from

burner and allow it to rest near

the boom of the water heater

cabinet for easier access.

Disconnecng Exhaust

Thermistor

Locate and disconnect the

exhaust thermistor wire

harness at the secondary heat

exchanger. See Figure 143.

NOTICE: To disconnect the exhaust

thermistor, use a pair of needle

nose pliers to gently press down

on the connector tab while pulling

connecons apart.

Exhaust

Thermistor

Press

Figure 143 - Disconnecng exhaust thermistor

Removing Hi-Limit Switch

Locate the hi-limit switch on

the primary heat exchanger

(top right side of water heater).

Disconnect the two wire leads from

the hi-limit switch. See Figure 144.

Wire leads are labeled: HIGH LIMIT 1

Screw

Wire

Lead

Wire

Lead

Figure 144 - Hi-Limit switch locaon

Steps 34 & 35 are only necessary

if replacing the primary HEX. If

replacing the secondary HEX, proceed

to Step 36.

Use a Phillips screwdriver to

remove the two screws

securing the hi-limit switch to the heat

exchanger. Place screws aside in a safe

place for reinstallaon. See Figure

144.

Remove hi-limit switch from

primary heat exchanger and

place aside in a safe place for

reinstallaon.

Disconnecng Primary HEX

Water Piping

Locate the inlet and outlet

water connecons on the

primary HEX. Remove the two spring

clips (size 25) securing the water

connecons and place them aside in a

safe place for reinstallaon.

Disconnect piping. See Figure 145.

Remove

Spring Clips

(size 25)

Figure 145 - Disconnecng primary HEX water

piping

Disconnecng Secondary HEX

Water Piping

Locate the inlet and outlet

water connecons on the

secondary HEX. Remove the two

spring clips (size 25) securing the

water connecons and place them

aside in a safe place for reinstallaon.

Disconnect piping. See Figure 146.

Remove

Spring Clips

(size 25)

Figure 146 - Disconnecng secondary HEX water

piping

Removing Primary HEX Heater

Cylinders

Locate the two heater cylinders

on the le and right side of the

primary HEX. The heater cylinders are

held in place by exible brackets.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 79

SERVICE (COMBUSTION COMPONENTS)

SERVICE

Use a Phillips screwdriver to

gently pry the exible brackets

away from the HEX to allow space for

the heater cylinders and wires to slide

out. Remove the two heater cylinders.

See Figure 147.

Remove

Heater Cylinder

(right side)

Pry

Bracket

Away From

HEX

Figure 147 - Removing primary HEX heang

cylinders

Removing Secondary HEX

Heater Cylinder

Locate the heater cylinder on

the le side of the secondary

HEX. The heater cylinder is held in

place by a exible bracket. Remove

the heater cylinder. See Figure 148.

Remove

Heater Cylinder

(top left side)

Figure 148 - Removing secondary HEX heang

cylinders

Removing Condensate Hose

Disconnect the black

condensate hose from the top

of the condensate trap and the

secondary HEX. Compress the spring

clamp and pull it down along with the

black hose. Place it aside in a safe

place for reinstallaon. See Figure

149.

Condensate

Hose

Spring

Clamp

Figure 149 - Removing black condensate hose

Removing Gas Valve Screws

Locate and remove the four

screws securing the gas valve

to the gas manifold. Place screws

aside in a safe place for reinstallaon.

See Figure 150.

Screws (4)

Inlet

Manifold

Figure 150 - Remove screws securing gas valve

Disconnecng Clear Gas Tube

Locate the clear gas tube

connected to the gas valve and

primary heat exchanger assembly.

Disconnect the clear gas tube from

the primary heat exchanger assembly.

See Figure 151.

Gas Tube

Clamp

Figure 151 - Disconnecng clear gas tube

Removing HEX Assembly

Liing Risk

WARNING! The

heat exchanger is

heavy. Follow these

precauons to reduce the risk of

property damage, injuries from liing

or impact injuries from dropping the

water heater.

Locate the boom horizontal

bracket and two (A) screws

securing the primary heat exchanger

assembly to the backside of the water

heater cabinet as shown in Figure 152.

Use a 12" magnezed Phillips

screwdriver to remove the screws.

Place them aside in a safe place for

reinstallaon.

Remove 2x (A) screws

Figure 152 - Removing primary HEX (A) screws

80 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (COMBUSTION COMPONENTS)

SERVICE

Locate the upper horizontal

bracket and two (B) screws

securing the primary heat exchanger

assembly to the backside of the water

heater cabinet as shown in Figure 153.

Use a 12" magnezed Phillips

screwdriver to remove the screws.

Place them aside in a safe place for

reinstallaon.

Remove 2x (B) screws

Figure 153 - Removing primary HEX (B) screws

Locate the two brackets and

four (C) screws securing the

secondary heat exchanger assembly

to the backside of the water heater

cabinet as shown in Figure 154. Use a

12" magnezed Phillips screwdriver to

remove the screws. Place them aside

in a safe place for reinstallaon.

Remove

4x (C) screws

Figure 154 - Removing secondary HEX (C)

screws

Locate the heat exchanger

install bracket and two screws

at the top of the water heater cabinet

as shown in Figure 155.

Install Bracket

Figure 155 - HEX install bracket and screws

WARNING! Once top screws are

removed from bracket the heat

exchanger will come free. Properly

support the weight of the heat

exchanger when removing screws.

Failure to properly support the

weight of the heat exchanger could

cause property damage or personal

injury.

Remove the top two screws

from install bracket. Allow heat

exchanger to drop slightly so it can be

disconnected from exhaust port then

li to remove heat exchanger from

the two cabinet support brackets and

the water heater. See Figure 156 and

Figure 157 for reference.

Figure 156 - Removing heat exchanger assembly

Cabinet Support

Brackets

Exhaust Port

Figure 157 - Cabinet support brackets

Remove the two heater

cylinder exible brackets and

screws secured to the HEX assembly.

Place brackets and screws aside in a

safe place for reinstallaon.

Once brackets have been

removed, locate the 24 screws

securing the primary heat exchanger

to the secondary heat exchanger.

Remove screws and place aside in a

safe place for reinstallaon. See Figure

158.

Screws (8)

Screws (4)

Screws

(8)

Figure 158 - Removing HEX assembly screws

Separate the primary and

secondary heat exchangers.

Preparing New Primary Heat

Exchanger for Installaon

(Kit 100390054 Only)

Locate the gas manifold on the

old primary heat exchanger.

Remove the eight screws securing the

gas manifold and place them aside in

a safe place for reinstallaon. See

Figure 159.

Gas

Manifold

Screws (8x)

Figure 159 - Removing gas manifold from old

primary heat exchanger

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 81

SERVICE (COMBUSTION COMPONENTS)

SERVICE

Remove gas manifold and place

it aside in a safe place for

reinstallaon.

Locate the overheat cuto fuse

(OHCF) above the burner

assembly. Remove the two guide clips

from the burner assembly roung the

OHCF around the primary heat

exchanger. Dispose of guide clips and

OHCF properly. See Figure 160.

Locate the (2x) boom screws

and (9x) top screws securing

the burner assembly to the old

primary heat exchanger as shown in

Figure 160. Use a 12" magnezed

Phillips screwdriver to remove screws.

Place screws aside in a safe place for

reinstallaon.

Top Burner Screws (9x)

Bottom Burner

Screws (2x)

Guide Clips

Figure 160 - Burner screws and guide clips

Remove burner assembly from

old primary heat exchanger.

Use a plasc scraper to gently

scrape old insulaon gasket

clean from primary heat exchanger

and burner assembly. Conrm

assembly surfaces are free of any

debris or leover insulaon. Install

burner assembly gasket to burner

assembly See Figure 161.

IMPORTANT! DO NOT gouge or

damage assembly surfaces when

removing insulaon gasket.

NOTICE: Handle with care and verify

gasket is not dirty or damaged.

Burner Assembly Gasket

Figure 161 - Replacing burner assembly gasket

Locate the new primary heat

exchanger provided in the kit.

Remove the two guide clips securing

the new OHCF. Install burner assembly

to new primary heat exchanger.

Secure burner assembly with the (2x)

boom screws and the (9x) top

screws previously removed in Step 55.

Resecure the new OHCF wire to

new primary HEX and burner

assembly using the guide clips

removed in Step 58. Conrm wire ts

snug into the four guide clips installed

to the front and backside of new

primary HEX.

Locate the gas manifold gasket

provided in the kit. Use a

plasc scraper to gently scrape old

insulaon gasket clean from gas

manifold. Conrm assembly surface is

free of any debris or leover

insulaon. Install new gasket to gas

manifold. See Figure 162.

IMPORTANT! DO NOT gouge or

damage assembly surface when

removing insulaon gasket.

NOTICE: Handle with care and verify

gasket is not dirty or damaged.

Gas Manifold Gasket

Figure 162 - Replacing gas manifold gasket

Install gas manifold to new

primary heat exchanger. Secure

gas manifold with the eight screws

previously removed in Step 52.

Locate the four new O-rings

provided in the kit. Remove the

old O-rings from inlet and outlet

water connecons for the HEX

assembly and replace with new

O-rings. See Figure 163.

NOTICE: Handle with care and verify

lubricant has been applied to O-rings.

Conrm O-rings are not dirty or

damaged.

O-rings

O-ring

Figure 163 - Replacing HEX O-rings

Dispose of old primary heat

exchanger properly.

The new primary heat exchanger is

now ready for installaon. Proceed to

the Installing Heat Exchanger secon

on the following page.

82 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (COMBUSTION COMPONENTS)

SERVICE

Preparing New Secondary Heat

Exchanger for Installaon

(Kit 100390052 Only)

Locate the HEX gasket provided

in the kit. Use a plasc scraper

to gently scrape old insulaon gasket

clean from the primary and secondary

heat exchangers. Conrm assembly

surfaces are free of any debris or

leover insulaon. Install new gasket

to primary heat exchanger. See Figure

164.

IMPORTANT! DO NOT gouge or

damage assembly surface when

removing insulaon gasket.

NOTICE: Handle with care and verify

gasket is not dirty or damaged.

HEX Gasket

Figure 164 - Replacing HEX gasket

Locate the four new O-rings

provided in the kit. Remove the

old O-rings from inlet and outlet

water connecons for the HEX

assembly and replace with new

O-rings. See Figure 163.

NOTICE: Handle with care and verify

lubricant has been applied to O-rings.

Conrm O-rings are not dirty or

damaged.

Dispose of old secondary heat

exchanger properly.

The new secondary heat exchanger is

now ready for installaon. Proceed to

the Installing Heat Exchanger secon.

Replacing OHCF Wire

(Kit 100390055 Only)

Remove the old OHCF wire

from the primary HEX. Dispose

of wire properly.

Locate the new OHCF wire

provided in the kit and install to

primary HEX. Conrm wire ts snug

into the four guide clips on the front

and backside of primary HEX.

Proceed to the Installing Heat

Exchanger secon.

Installing Heat Exchanger

Liing Risk

WARNING! The

heat exchanger is

heavy. Follow these

precauons to reduce the risk of

property damage, injuries from liing

or impact injuries from dropping the

water heater.

Secure primary HEX to

secondary HEX with the 24

screws previously removed in Step 50.

See Figure 158 as reference.

Secure the two heater cylinder

exible brackets and screws to

HEX assembly previously removed in

Step 49.

Locate the top two install

bracket screws previously

removed in Step 48. Place both screws

and a Phillips screwdriver on top of

water heater cabinet for ease of

access when installing heat exchanger

assembly.

Li heat exchanger assembly

into water heater cabinet. Lean

the top side of heat exchanger slightly

toward you so the two tabs on the

backside of the secondary heat

exchanger insert into the two cabinet

support brackets as shown in Figure

157.

Once the tabs are inserted, push heat

exchanger upright into exhaust port so

screw holes in the install bracket align

properly with the top bracket on the

secondary heat exchanger as shown in

Figure 165.

Screw Holes (2x)

in Brackets

Must Align

Figure 165 - Align screw holes in brackets

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 83

SERVICE (COMBUSTION COMPONENTS)

SERVICE

Hold heat exchanger in place

and secure with the top two

screws placed on the water heater

cabinet in Step 71.

NOTICE: Verify all 8 screw hole

locaons on the primary and

secondary heat exchangers properly

align with screw holes in the water

heater cabinet and horizontal

brackets. To realign heat exchanger

screw holes, li heat exchanger from

underneath and shi upward to

center the assembly.

Locate the four secondary heat

exchanger mounng screws

previously removed in Step 46. Use a

12" magnezed Phillips screwdriver

and four screws to secure the heat

exchanger to the water heater

cabinet. See Figure 154.

Locate the four primary heat

exchanger mounng screws

previously removed in Steps 44 & 45.

Use a 12" magnezed Phillips

screwdriver and four screws to secure

the heat exchanger to the two

horizontal brackets. See Figure 152 &

Figure 153.

IMPORTANT! The heat exchanger is

now secured to the water heater and

fully supported.

Connecng Clear Gas Tube

Locate the clear gas tube

previously disconnected in

Step 43. Connect the clear gas tube to

the primary heat exchanger. See

Figure 151.

Securing Gas Valve

Locate the four gas valve

screws previously removed in

Step 42. Secure gas valve to the gas

manifold and heat exchanger

assembly. See Figure 150.

Installing Black Condensate

Hose

Locate the black condensate

hose previously removed in

Step 41. Connect the hose to the

secondary HEX. Make sure the hose is

fully seated along with the spring

clamp. Reaach the other end of the

hose to the top of the condensate

trap. Check the connecons to ensure

they are fully seated to prevent leaks.

See Figure 149.

Installing HEX Heang

Cylinders

Locate the heang cylinders

previously removed from the

primary and secondary heat

exchangers in Steps 39 & 40. Slide

heat cylinders into brackets so

cylinders sit ush against heat

exchangers. See Figure 147 and Figure

148 as reference.

Connecng HEX Water Piping

Connect the inlet and outlet

water piping to the primary

and secondary heat exchangers

previously disconnected in Steps 36 &

37. Secure piping connecons with

the four spring clips (size 25). Conrm

connecons are ght and will not

leak. See Figure 145 and Figure 146

for reference.

Installing Hi-Limit Switch

If the primary HEX assembly

was removed, locate the

hi-limit switch and two screws

previously removed in Steps 34 & 35.

Install hi-limit switch to primary heat

exchanger and secure with the two

screws.

Reconnect the wire leads to

hi-limit switch previously

disconnected in Step 33. See Figure

144 as reference.

Connecng Exhaust Thermistor

Connect the exhaust thermistor

wire harness to the secondary

heat exchanger previously

disconnected in Step 32. See Figure

143.

Installing Fan Assembly

Locate the fan assembly and

ve screws previously removed

in Steps 29-31. Install fan assembly

outlet rmly into burner. Verify all

screw hole locaons align properly.

Secure fan assembly with the ve

screws, starng with the bracket

screw (C) to help stabilize the fan

assembly. See Figure 141 & Figure

142.

Connecng Overheat Cuto

Fuse (OHCF) Wire

Locate the OHCF wire

previously disconnected in Step

28. Connect the wire. See Figure 140.

84 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Connecng Gas Manifold Wire

Harness

Locate the gas manifold wire

harness previously

disconnected in Step 27 and connect

it. See Figure 139.

Installing Flow Control Valve

Locate the ow control valve

and two spring clips (size 25)

previously removed in Steps 24-26.

Carefully install ow control valve to

pipe connecons. Install spring clips to

ow control valve, securing it to

piping connecons. Verify water

connecons are ght and will not

leak. See Figure 138.

Installing the Ignitor Assembly

Locate the ignitor assembly and

two screws previously removed

in Steps 20-23. Connect the two spade

terminal connecons to the ignitor

assembly. Conrm electrical

connecons are ght.

NOTICE: There is one large and one

small spade terminal connecon.

Mount the ignitor assembly to

the gas manifold and secure

with the two screws.

Reconnect the ignitor wire

previously removed in Step 21.

Installing UIM and Bracket

Secure the User Interface

Module (UIM) and bracket to

water heater with the four screws

previously removed in Step 19.

Conrm all electrical connecons are

snug and properly routed behind

bracket. See Figure 135.

Connect the two green ground

wires previously disconnected

in Step 18. See Figure 134.

Connecng Flame Sensor Wire

Verify ame sensor wire is

connected to the primary heat

exchanger and PCB. This wire was

previously disconnected in Step 17.

See Figure 133.

Checking for Water Leaks

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Checking for Gas Leaks

IMPORTANT! DO NOT apply liquids

to any of the electrical connecons

when checking for gas leaks. Use a

towel or rag to protect any electrical

components.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater.

Open all hot water xtures in

the house. This will iniate the

call for heat at the water heater.

Use code approved methods to

check for leaks around all gas

connecon points and the heat

exchanger. To protect electrical

connecons, DO NOT perform a

bubble test. If any leaks are detected,

resecure components and recheck for

leaks.

Proceed to the next secon

once there are no leaks

detected.

Returning Water Heater to

Operaon

100

Replace the cabinet cover and

secure with the screws

previously removed in Step 15.

The water heater is now ready for

operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 85

SERVICE

SERVICE (COMBUSTION COMPONENTS)

Water Inlet Assembly

Kit 100389977 Contains:

• Inlet Assembly

• O-ring (15.5 x 2.5)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Thread Sealant/Pipe Dope

• Towel or Rag

• Bucket or Pan

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Draining the Water Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three (3) screws

securing the X3®/Bypass

cartridge as shown in Figure 166.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 166 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 167 to

drain any residual water le in the

system.

Inlet

Filter

Figure 167 - Locate and remove inlet lter

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Reinstall the cartridge to the

water heater. Insert the

cartridge into manifold and secure

with the two (2) long screws and one

(1) short screw previously set aside in

Step 6.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Insert and snug all three (3)

screws by hand. Use a

screwdriver to ghten the two

screws rst and lastly ghten screw

. DO NOT use a drill or impact

driver to ghten the screws.

Disconnect the cold water line

to the cold inlet assembly.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components

Disconnecng UIM and Bracket

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon. See Figure 168.

86 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (WETTED COMPONENTS)

NOTICE: UIM, bracket and wiring

do not need to be disconnected.

Allow UIM and bracket to rest below

water heater for easy access to inlet

assembly.

Remove

4 screws

Figure 168 - Removing UIM and bracket screws

Removing the Inlet Assembly

Locate the spring clip (size 25)

securing inlet assembly to ow

control valve. Remove spring clip and

place aside in a safe place for

reinstallaon. See Figure 169.

Flow Control

Valve

Spring Clip

Figure 169 - Inlet assembly locaon

CAUTION! Water may sll be

present in the valve assembly. Place a

rag under the valve connecon points

to prevent water from escaping into

the water heater cabinet.

Locate the screw securing the

heater block in the base of the

inlet assembly. See Figure 170. Use a

Phillips screwdriver to remove the

screw. Place the screw aside in a safe

place for reinstallaon.

Remove the heater block from

the base and set aside for

reinstallaon.

Heater Block

Screw

Figure 170 - Heater block locaon

Locate the inlet assembly at the

boom right side of the water

heater as shown in Figure 171.

Locate the three (3) screws

securing the inlet assembly to

the base of the water heater. Use a

Phillips screwdriver to remove the

screws. Place screws aside in a safe

place for reinstallaon. See Figure

171.

Screws

Figure 171 - Inlet assembly locaon

Remove the old inlet assembly

from the piping system and

dispose of properly.

Installing New Inlet Assembly

Locate the new inlet assembly

and O-ring provided in the kit.

Place the new O-ring on the

new inlet assembly.

NOTICE: Handle with care and verify

lubricant has been applied to O-rings

and O-rings are not dirty or damaged.

Place the new inlet assembly in

the water heater and secure

with the screws removed in Step 20.

Reinstall the heater block to

the base of the inlet assembly

and secure with the screw removed in

Step 17.

Locate the spring clip (size 25)

previously removed in Step 16.

Secure inlet assembly to ow control

valve with spring clip.

Reconnect the cold water line

disconnected in Step 12. Use

thread sealant tape or pipe dope

when making the connecon.

Installing UIM and Bracket

Secure the User Interface

Module (UIM) and bracket to

water heater with the four screws

previously removed in Step 15.

Conrm all electrical connecons are

snug and properly routed behind

bracket.

Checking for Water Leaks

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 13.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 87

SERVICE

SERVICE (WETTED COMPONENTS)

88 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (WETTED COMPONENTS)

Flow Control Valve

Kit 100389978 Contains:

• Flow Control Valve

• (2x) O-ring (15.5 x 2.5)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Bucket or Pan

• Towel or Rag

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Draining the Water Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three (3) screws

securing the X3®/Bypass

cartridge as shown in Figure 172.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 172 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 173 to

drain any residual water le in the

system. Place a bucket or pan

underneath inlet lter to collect water

during removal.

Inlet

Filter

Figure 173 - Removing the inlet lter

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Reinstall the cartridge to the

water heater. Locate the screws

previously removed in Step 6. Insert

and snug all three (3) screws by hand.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Use a screwdriver to ghten

the two

screws rst and

lastly ghten screw

. DO NOT use a

drill or impact driver to ghten the

screws.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Removing Flow Control Valve

Locate the ow control valve

behind the user interface

module (UIM) bracket in the water

heater as shown in Figure 174.

Disconnect the three (3) wiring

harnesses to the valve marked:

• "Main Water Valve"

• "Inlet" (Blue)

• "Flow" (White)

To disconnect the "Inlet" and "Flow"

connecons, use a pair of needle

nose pliers to gently press down

on the connector tab while pulling

connecons apart. See Figure 175.

NOTICE: Some components and wiring

have been removed for clarity.

Main Water Valve

Inlet

Flow

Figure 174 - Locang wiring harnesses

Press

Figure 175 - Disconnecng inlet and ow

Remove the two (2) spring clips

(size 25) securing the ow

control valve to the piping system.

Place the spring clips aside in a safe

place for reinstallaon. See Figure

176.

CAUTION! Water may sll be

present in the valve assembly. Place a

rag under the valve connecon points

to prevent water from escaping into

the water heater cabinet.

Spring Clip

Flow Control Valve

Figure 176 - Removing spring clips from ow

control valve

Remove the ow control valve

from the piping system and

dispose of properly.

Installing New Flow Control

Valve

Locate the two O-rings on the

exposed water pipe

connecons as shown in Figure 177

and remove them. Dispose of O-rings

properly.

Remove

O-rings

Figure 177 - Locang and removing O-rings

Locate the two (2) O-rings

provided in the kit.

Install new O-rings to exposed

water pipe connecons.

NOTICE: Handle with care and verify

lubricant has been applied to O-rings

and O-rings are not dirty or damaged.

Locate the new ow control

valve provided in the kit.

Carefully install ow control valve to

pipe connecons.

Locate the two (2) spring clips

previously removed in Step 15.

Install spring clips to ow control

valve, securing it to piping

connecons. See Figure 176. Verify

water connecons are ght and will

not leak.

Reconnect the three (3) wiring

harnesses to the ow control

valve previously disconnected in

Step 14. Conrm wiring connecons

are secure. See Figure 174.

Checking for Water Leaks

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 12.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 89

SERVICE

SERVICE (WETTED COMPONENTS)

Cartridge Manifold

Kit 100374732 Contains:

• Cartridge Manifold

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Bucket or Pan

• Towel or Rag

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Draining the Water Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three (3) screws

securing the X3®/Bypass

cartridge as shown in Figure 178.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 178 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 179 to

drain any residual water le in the

system. Place a bucket or pan

underneath inlet lter to collect water

during removal.

Inlet

Filter

Figure 179 - Removing the inlet lter

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Disconnecng UIM and Bracket

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon. See Figure 180.

NOTICE: UIM, bracket and wiring do

not need to be disconnected. Allow

UIM and bracket to rest below water

heater for easy access to cartridge

manifold.

Remove

4 screws

Figure 180 - Removing UIM and bracket screws

90 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (WETTED COMPONENTS)

Preparing Cartridge Manifold

for Removal

Locate and remove the two

spring clips (size 25) securing

the manifold inlet tube and outlet

tube to cartridge manifold. Place the

spring clips aside in a safe place for

reinstallaon. See Figure 181.

CAUTION! Water may sll be

present in the valve assembly. Place a

rag under the valve connecon points

to prevent water from escaping into

the water heater cabinet.

Spring Clips

Manifold

Figure 181 - Remove two spring clips from the

cartridge manifold.

Removing Cartridge Manifold

Locate the three (3) screws

securing the cartridge manifold

to the underside of the water heater

cabinet as shown in Figure 182. Use a

Phillips screwdriver to remove screws.

Place screws aside in a safe place for

reinstallaon.

Screws

Screw

Figure 182 - Remove manifold screws

Remove the old cartridge

manifold from the piping

system and dispose of properly.

Installing Cartridge Manifold

Locate the new cartridge

manifold provided in the kit.

Locate the three (3) screws

previously removed in Step 13.

Use screws to secure cartridge

manifold to water heater cabinet. See

Figure 182.

With cartridge manifold

secured, reconnect the

manifold inlet tube and outlet tube.

Secure with the two spring clips (size

25) previously removed in Step 12.

Checking for Water Leaks

Reinstall the cartridge to the

water heater. Locate the screws

previously removed in Step 5. Insert

and snug all three (3) screws by hand.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Use a screwdriver to ghten

the two

screws rst and

lastly ghten screw

. DO NOT use a

drill or impact driver to ghten the

screws.

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Installing UIM and Bracket

Secure the User Interface

Module (UIM) and bracket to

water heater with the four screws

previously removed in Step 11.

Conrm all electrical connecons are

snug and properly routed behind

bracket.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 9.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 91

SERVICE

SERVICE (WETTED COMPONENTS)

Bypass Valve

Kit 100371165 Contains:

• Bypass Valve

• (2x) O-ring (15.5 x 2.5)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Bucket or Pan

• Towel or Rag

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Draining the Water Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three (3) screws

securing the X3®/Bypass

cartridge as shown in Figure 183.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 183 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 184 to

drain any residual water le in the

system. Place a bucket or pan

underneath inlet lter to collect water

during removal.

Inlet

Filter

Figure 184 - Removing the inlet lter

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Reinstall the cartridge to the

water heater. Locate the screws

previously removed in Step 6. Insert

and snug all three (3) screws by hand.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Use a screwdriver to ghten

the two

screws rst and

lastly ghten screw

. DO NOT use a

drill or impact driver to ghten the

screws.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

92 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (WETTED COMPONENTS)

Removing Bypass Valve

Locate the bypass valve on the

le side of the water heater as

shown in Figure 185.

Spring Clips

(size 25)

Black Wire Protector

Bypass

Valve

Wiring Harness

Figure 185 - Bypass valve

Remove the black wire protector

from bypass valve and place it aside

in a safe place for reinstallaon.

Disconnect the wiring harness from

the valve.

CAUTION! Water may sll be

present in the valve assembly. Place a

rag under the valve connecon points

to prevent water from escaping into

the water heater cabinet.

Remove the two (2) spring clips

(size 25) securing the bypass

valve to the piping system. Place the

spring clips aside in a safe place for

reinstallaon.

Remove the bypass valve from

the piping system and dispose

of properly.

Installing New Bypass Valve

Locate the two O-rings on the

exposed water pipe

connecons as shown in Figure 186

and remove them. Dispose of O-rings

properly.

Replace O-rings

Figure 186 - Replace exposed O-rings

Locate the two (2) O-rings

provided in the kit.

Install new O-rings to exposed

water pipe connecons.

NOTICE: Handle with care and verify

lubricant has been applied to O-rings

and O-rings are not dirty or damaged.

Locate the new bypass valve

provided in the kit. Carefully

install bypass valve to pipe

connecons.

Locate the two (2) spring clips

previously removed in Step 15.

Install spring clips to bypass valve,

securing it to piping connecons.

Verify water connecons are ght and

will not leak.

Reconnect wiring harness to

bypass valve. Conrm wiring

connecon is secure. Reinstall the

black wire protector removed in

Step 14.

Checking for Water Leaks

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 12.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 93

SERVICE

SERVICE (WETTED COMPONENTS)

Water Outlet Assembly

Kit 100390057 Contains:

• Outlet Assembly

• O-ring (17.8 x 2.4)

• O-ring (3.8 x 1.9)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Thread Sealant/Pipe Dope

• Towel or Rag

• Bucket or Pan

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Draining the Water Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three (3) screws

securing the X3®/Bypass

cartridge as shown in Figure 187.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 187 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 188 to

drain any residual water le in the

system.

Inlet

Filter

Figure 188 - Locate and remove inlet lter

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Reinstall the cartridge to the

water heater. Insert the

cartridge into manifold and secure

with the two (2) long screws and one

(1) short screw previously set aside in

Step 6.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Insert and snug all three (3)

screws by hand. Use a

screwdriver to ghten the two

screws rst and lastly ghten screw

. DO NOT use a drill or impact

driver to ghten the screws.

Disconnect the hot water line

to the hot outlet assembly.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components

94 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (WETTED COMPONENTS)

Removing the Outlet Assembly

Locate the C clip securing the

outlet assembly to the water

piping. Remove the two screws

securing C clip. Place screws and C clip

aside in a safe place for reinstallaon.

See Figure 189.

Screws

C Clip

Thermistor

Heater Block

Outlet Tube

Figure 189 - Removing C clip and screws

CAUTION! Water may sll be

present in the valve assembly. Place a

rag under the valve connecon points

to prevent water from escaping into

the water heater cabinet.

Pull the heater block and

thermistor from the base of the

outlet assembly and set aside for

reinstallaon.

Locate the three (3) screws

securing the outlet assembly to

the base of the water heater. Use a

Phillips screwdriver to remove the

screws. Place screws aside in a safe

place for reinstallaon. See Figure

190.

Screws

Figure 190 - Outlet assembly screw locaon

Disconnect outlet assembly

from water piping and remove

the old outlet assembly from the

water heater. Dispose of outlet

assembly properly.

Installing New Outlet assembly

Locate the new outlet assembly

and large O-ring (17.8 x 2.4)

provided in the kit.

Install the new large O-ring to

water piping connecon as

shown in Figure 191.

Outlet Tube

O-ring

Figure 191 - Installing O-ring to water piping

NOTICE: Handle with care and verify

lubricant has been applied to O-rings

and O-rings are not dirty or damaged.

Place the new outlet assembly

in the water heater and secure

from below with the screws removed

in Step 17.

Locate the small O-ring

(3.8 x 1.9) provided in the kit.

Place the O-ring over the thermistor

and install it in the base of the outlet

assembly. See Figure 192.

O-ring

Thermistor

Figure 192 - Installing O-ring to thermistor

Reinstall the heater block to

the base of the outlet

assembly. Secure heater block and

thermistor with C clip and two screws

previously removed in Step 15. Verify

water connecons are ght and will

not leak.

Reconnect the hot water line

disconnected in Step 12. Use

thread sealant tape or pipe dope

when making the connecon.

Checking for Water Leaks

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 13.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 95

SERVICE

SERVICE (WETTED COMPONENTS)

Water Tubing

Kit 100389979 (T1) Contains:

• Inlet Manifold Tube

• (2x) O-ring (15.5 x 2.5 NBR)

• Kit Instrucons

Kit 100389980 (T2) Contains:

• Outlet Manifold Tube

• (1x) O-ring (15.5 x 2.5 NBR)

• (1x) O-ring (15.5 x 2.5 EPDM)

• Kit Instrucons

Kit 100390051 (T3) Contains:

• Secondary HEX Inlet Tube

• (3x) O-ring (15.5 x 2.5 NBR)

• Kit Instrucons

Kit 100390056 (T4) Contains:

• Primary HEX Outlet Tube

• (2x) O-ring (15.5 x 2.5 NBR)

• (1x) O-ring (17.8 x 2.4 NBR)

• (1x) O-ring (3.8 x 1.9 NBR)

• Kit Instrucons

Kit 100390053 (T5) Contains:

• HEX Assembly Tube

• (2x) O-ring (15.5 x 2.5 NBR)

• (2x) O-ring (5.8 x 1.9 EPN)

• Kit Instrucons

Kit 100390058 (T6) Contains:

• Drain Tube

• (2x) O-ring (5.8 x 1.9 EPN)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Bucket or Pan

• Towel or Rag

• Safety Gloves

(T1-T6) Preparing Water Heater

for Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote

DOES NOT disconnect power to the

water heater. You must physically

disconnect power to the water heater.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

(T1-T6) Draining the Water

Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three (3) screws

securing the X3®/Bypass

cartridge as shown in Figure 193.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 193 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 194 to

drain any residual water le in the

system. Place a bucket or pan

underneath inlet lter to collect water

during removal.

Inlet

Filter

Figure 194 - Removing the inlet lter

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Reinstall the cartridge to the

water heater. Locate the screws

previously removed in Step 5. Insert

and snug all three (3) screws by hand.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Use a screwdriver to ghten

the two

screws rst and

lastly ghten screw

. DO NOT use a

drill or impact driver to ghten the

screws.

96 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (WETTED COMPONENTS)

(T1-T6) Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon. Allow UIM and bracket

to rest below water heater for easier

access.

NOTICE: Use the parts diagram

(Figure 195) on page 99 as a guide

to assist in removing and replacing

water tubing assemblies.

IMPORTANT! When tube

replacement is complete, proceed

to the "Checking for Water Leaks"

secon.

(T1) Replacing Inlet Manifold

Tube (Kit 100389979)

Remove spring clips (S1 & S2)

from manifold assembly (P1)

and ow control valve (P2).

Disconnect inlet manifold tube (T1)

and dispose of properly.

Install new O-rings (R1 & R2) to

new inlet manifold tube. Secure

new inlet manifold tube to manifold

assembly (P1) and ow control valve

(P2) with spring clips (S1 & S2).

(T2) Replacing Outlet Manifold

Tube (Kit 100389980)

Remove spring clips (S3 & S4)

from manifold assembly (P1)

and secondary HEX inlet tube (T3).

Remove heater block from tube.

Disconnect outlet manifold tube (T2)

and dispose of properly.

Install new "EPDM" O-ring (R3)

to manifold assembly (P1).

Install new "NBR" O-ring (R4) to new

outlet manifold tube. Secure new

outlet manifold tube to manifold

assembly (P1) and secondary HEX

inlet tube (T3) with spring clips (S3 &

S4). Install heater block.

(T3) Replacing Secondary HEX

Inlet Tube (Kit 100390051)

Remove spring clips (S4, S5 &

S6) from outlet manifold tube

(T2), bypass valve (P5) and secondary

HEX inlet. Remove heater block from

tube. Disconnect secondary HEX inlet

tube (T3) and dispose of properly.

Install new O-ring (R4) to outlet

manifold tube (T2).

Install new O-rings (R5 & R6) to

new secondary HEX inlet tube

connecons. Secure new secondary

HEX inlet tube to outlet manifold tube

(T2), bypass valve (P5) and secondary

HEX inlet with spring clips (S4, S5 &

S6). Install heater block.

(T4) Replacing Primary HEX

Outlet Tube (Kit 100390056)

Remove spring clips (S7 & S8)

from bypass valve (P5) and

primary HEX outlet.

Remove two screws and C clip

(P8) securing primary HEX

outlet tube (T4) to outlet assembly

(P4).

Remove screw, bracket and

outlet thermistor (P6) from

primary HEX outlet tube (T4).

Remove thermostat (P7) and

two heater blocks. Disconnect

primary HEX outlet tube and dispose

of properly.

Install new small O-rings (R7,

R8) and new large O-ring (R9)

to new primary HEX outlet tube

connecons. Secure new primary HEX

outlet tube to bypass valve (P5) and

primary HEX outlet with spring clips

(S7 & S8). Secure new primary HEX

outlet tube to outlet assembly (P4)

with C clip (P8) and two screws.

Install new O-ring (R14) to

outlet thermistor (P6). Install

outlet thermistor (P6) and bracket to

new primary HEX outlet tube and

secure with screw.

Install thermostat (P7) and two

heater blocks.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 97

SERVICE

SERVICE (WETTED COMPONENTS)

98 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE (WETTED COMPONENTS)

SERVICE

(T5) Replacing HEX Assembly

Tube (Kit 100390053)

Remove spring clips (S5 & S6)

from bypass valve (P5) and

secondary HEX inlet. Parally

disconnect secondary HEX inlet tube

(T3) for easier access to HEX assembly

tube (T5).

Remove spring clips (S9, S10 &

S11) from secondary HEX,

primary HEX and drain tube (T6).

Remove heater block from tube.

Disconnect HEX assembly tube (T5)

and dispose of properly.

Install new O-rings (R10 & R11)

to new HEX assembly tube.

Install new O-ring (R12) to

drain tube (T6).

Secure new HEX assembly tube

to drain tube (T6) rst. Secure

with spring clip (S11).

Secure new HEX assembly tube

to secondary HEX and primary

HEX with spring clips (S9 & S10).

Install heater block.

Secure secondary HEX inlet

tube (T3) to bypass valve (P5)

and secondary HEX inlet with spring

clips (S5 & S6).

(T6) Replacing Drain Tube

(Kit 100390058)

Remove spring clips (S11 &

S12) from HEX assembly tube

(T5) and condensate drain connecon

(P3). Disconnect drain tube (T6) and

dispose of properly.

Install new O-rings (R12 & R13)

to new drain tube. Secure new

drain tube to HEX assembly tube (T5)

and condensate drain connecon (P3)

with spring clips (S11 & S12).

(T1-T6) Checking for Water

Leaks

Turn ON the cold water supply to

the water heater at the cold inlet

valve. The system will fully pressurize

and any leaks at water connecons

will be apparent. Correct any leaks

immediately and dry water heater

cabinet with a rag.

(T1-T6) Returning Water

Heater to Operaon

Secure the User Interface Module

(UIM) and bracket to water heater

with the four screws previously

removed in Step 13 (page 1). Conrm

all electrical connecons are snug and

properly routed behind bracket.

Replace the cabinet cover and secure

with the screws previously removed in

Step 11 (page 1).

Restore power to water heater.

The water heater is now ready for

operaon.

R14

S10

S11

S12

R10

R11

R12

R13

Figure 195 - Water tubing connecon reference guide

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 99

SERVICE (WETTED COMPONENTS)

SERVICE

Condensate Trap

Kit 100390066 Contains:

• Condensate Trap

• Condensate Hose

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Flat Head Screwdriver

• Towel or Rag

• Bucket or Pan

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Accessing Condensate Trap

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon.

NOTICE: UIM, bracket and wiring

do not need to be disconnected.

Allow UIM and bracket to rest below

water heater for easy access to the

condensate trap.

Removing Condensate Trap

The condensate trap drain is

located underneath the water

heater (see Figure 199). Disconnect

drain piping to the plasc condensate

drain. Place a bucket or pan

underneath to collect water during

removal.

Locate the condensate trap at

the interior le rear side of the

water heater.

Trace the yellow wires from the

condensate trap to the red

wiring harness and disconnect them.

See Figure 196.

NOTICE: The harness uses a black

security clip. Use a small at blade

screwdriver to remove and keep this

clip for reinstallaon. See Figure 1.

Security Clip

Lift Here

Red Wiring

Harness

Figure 196 - Red wiring harness clip removal

Trace the black wires from the

condensate trap to the wiring

harness labeled "Liquid Level."

Disconnect the wires. See Figure 197.

Press Here

Liquid Level

Wiring Harness

Figure 197 - Liquid level wiring harness locaon

Disconnect the black hose from

the top of the condensate trap

and then from the front of the heat

exchanger (HEX). Compress the spring

clamp and pull it down along with the

black hose. Place the spring clamp

aside in a safe place for reinstallaon.

Dispose of condensate hose properly.

See Figure 198.

Condensate

Hose

Spring

Clamp

Figure 198 - Condensate hose removal

Locate the three (3) screws

underneath the water heater

securing the condensate trap. See

Figure 199. Use a Phillips screwdriver

to remove the screws. Place screws

aside in a safe place for reinstallaon.

100 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (WETTED COMPONENTS)

Screws

Condensate Trap (Bottom)

Figure 199 - Locaon of condensate trap screws.

Carefully remove the old

condensate trap and dispose of

it properly.

NOTICE: It is necessary to li the

condensate trap slightly and rotate it

within the unit, so that the rounded

secon is in the front. Then lt it

forward so that the rounded secon is

on the boom.

Installing New Condensate

Trap

Locate the new condensate

trap provided in the kit.

Carefully install the new condensate

trap.

NOTICE: When installing the new

condensate trap, orient with the

boom facing the heater and the

round secon on the boom.

Secure the condensate trap

with the three (3) screws

removed in Step 12.

Route the new red wiring

harness to its mate

disconnected in Step 9.

NOTICE: Carefully insert the black

safety clip into the red wiring harness.

See Figure 200.

Security Clip

Red Wiring Harness

Figure 200 - Reconnecng the wiring harness

Route and reconnect the black

wire to its mate removed in

Step 10.

Locate the new condensate

hose provided in the kit. Aach

the hose to the heat exchanger. Make

sure the hose is fully seated along

with the spring clamp previously

removed in Step 11. Reaach the

other end of the hose to the top of

the condensate trap. Check the

connecons to ensure they are fully

seated to prevent leaks.

Reconnect the condensate

drain piping removed in Step 7.

Returning Water Heater to

Operaon

Secure the User Interface

Module (UIM) and bracket to

water heater with the four screws

previously removed in Step 6. Conrm

all electrical connecons are snug and

properly routed behind bracket.

Replace the cabinet cover and

secure with the screws

previously removed in Step 4

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Turn ON the cold water supply

to the water heater at the cold

inlet valve.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 101

SERVICE

SERVICE (WETTED COMPONENTS)

Heat Exchanger (HEX)

Drain

Kit 100390059 Contains:

• HEX Drain

• (1x) O-ring (5.8 x 1.9)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Bucket or Pan

• Towel or Rag

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Draining the Water Heater

Drain the X3®/Bypass Cartridge.

Place a bucket or pan

underneath cartridge to collect water

during removal.

Locate the three (3) screws

securing the X3®/Bypass

cartridge as shown in Figure 201.

Remove the

M4-12mm screw and

the two

M4-25mm screws from

cartridge. Place screws aside in a safe

place for reinstallaon.

Figure 201 - Idenfy cartridge screws

Pull down to remove the

cartridge from the water

heater. Wait a few minutes to ensure

all water has completely drained.

Locate and remove the inlet

lter as shown in Figure 202 to

drain any residual water le in the

system. Place a bucket or pan

underneath inlet lter to collect water

during removal.

Inlet

Filter

Figure 202 - Removing the inlet lter

Once the water heater has

been adequately drained,

reinstall inlet lter to water heater

and ghten by hand. Conrm inlet

lter is secured to water heater.

Reinstall the cartridge to the

water heater. Locate the screws

previously removed in Step 5. Insert

and snug all three (3) screws by hand.

NOTICE: The X3® cartridge is keyed

to only install in one direcon. Align

the

on the cartridge with the

on the manifold (the arrows will

be facing the backside of the water

heater). When inserng the cartridge,

push up unl the screw holes align.

Some resistance is normal. The bypass

cartridge is not keyed and will install

in either direcon.

Use a screwdriver to ghten

the two

screws rst and

lastly ghten screw

. DO NOT use a

drill or impact driver to ghten the

screws.

Locate the heat exchanger

(HEX) drain line underneath the

water heater. See Figure 203. Remove

the two screws securing the metal

bracket and place them aside in a safe

place for reinstallaon.

Bracket

Screws

Plug

Figure 203 - HEX drain assembly

Remove the HEX drain plug by

twisng and pulling down.

Allow the HEX drain to drain

completely before moving to

the next step.

Accessing Water Heater

Components

Locate the two screws at the

boom of the cabinet cover.

Use a Phillips screwdriver to remove

the screws. Place screws aside in a

safe place for reinstallaon.

102 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (WETTED COMPONENTS)

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Disconnecng HEX Drain

Connecon

Locate the HEX drain connected

to the drain tube in the water

heater (boom le side). Remove

spring clip securing HEX drain to drain

tube and place it aside in a safe place

for reinstallaon. See Figure 203.

Spring Clip

HEX

Drain

Drain Tube

Figure 204 - Removing spring clip from HEX

drain

The HEX drain can now be

removed from the water

heater. Dispose of HEX drain properly.

CAUTION! Water may sll be

present in the HEX drain. Place a rag

under the drain connecon point to

prevent water from escaping into the

water heater cabinet.

Installing New HEX Drain

Locate the new HEX drain and

O-ring provided in the kit.

Remove old O-ring from drain tube

and install new O-ring as shown in

Figure 204.

Replace

O-ring

Drain Tube

Figure 205 - Replacing drain tube O-ring

Install new HEX drain from

underneath water heater

cabinet and connect it to the drain

tube. Orient HEX drain so screw holes

in drain and water heater cabinet

align.

Secure HEX drain to water

heater cabinet with the bracket

and two screws previously removed in

Step 11.

Secure HEX drain to drain tube

with the spring clip previously

removed in Step 16.

Checking for Water Leaks

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 14.

Restore power to the water

heater. The water heater is now

ready for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 103

SERVICE

SERVICE (WETTED COMPONENTS)

Inlet Water Filter

Kit 100371184 Contains:

• Inlet Filter

• O-ring (2.4 x 12)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Pliers

• Towel or Rag

• Bucket or Pan

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Place a bucket or pan

underneath the water heater

to collect water during removal.

Remove the old inlet lter and

dispose of it properly. Allow

water heater to drain.

Installing New Inlet Filter

Locate the new inlet lter and

O-ring provided in the kit.

Install the O-ring to the inlet lter. See

Figure 205.

NOTICE: Handle with care and verify

lubricant has been applied to O-ring

and O-ring is not dirty or damaged.

Inlet Filter Assembly

O-ring

Figure 206 - O-ring locaon

Install the new inlet lter to

water heater hand ght. Use

cauon and DO NOT damage the inlet

lter.

Returning Water Heater to

Operaon

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately.

Restore power to the water

heater. The water heater is now

ready for operaon.

104 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (WETTED COMPONENTS)

Emission Port Cap

Kit 100371166 Contains:

• Emission Port Cap

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Safety Gloves

WARNING!

This kit shall be installed

by a qualied service

agency in accordance

with the manufacturer’s

instructions and all

applicable codes

and requirements of

the authority having

jurisdiction. The

information in these

instructions must be

followed to minimize the

risk of re or explosion

or to prevent property

damage, personal

injury or death. The

qualied service agency

is responsible for the

proper installation of this

kit.

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Removing Emissions Port Cap

Locate the emission port cap at

the outlet exhaust port on the

water heater as shown in Figure 206.

Screw Covers

Figure 207 - Emission port locaon

Li the screw covers to reveal

the screws securing emission

port cap to exhaust port.

Remove screws and set aside in

a safe place for reinstallaon.

See Figure 207.

Screw Covers

Screws

Figure 208 - Emissions port screw removal

Remove emission port cap and

dispose of properly.

Installing New Emission Port

Cap

Locate the new emission port

cap provided in the kit.

Orient cap such that the plug

can be inserted into the outlet

exhaust port. Install cap to outlet

exhaust port.

Locate screws previously

removed in Step 5. Use screws

to secure cap to outlet exhaust port.

Cover screws with screw covers.

Checking for Gas Leaks

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater.

Open all hot water xtures in

the house. This will iniate the

call for heat at the water heater.

Check for leaks around the

emission port cap. Use a small,

so-bristled brush to apply a hand

dishwashing soap and water mixture

(1 part soap to 15 parts water) or

children’s soap bubbles around the

emissions port cap. If any leaks are

detected (which will appear as small

bubbles), resecure the emission port

cap and recheck for leaks.

Returning the Water Heater to

Operaon

The water heater is ready for

operaon once there are no

leaks detected at the emission port

cap.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 105

SERVICE

SERVICE (FLUE & AIR INTAKE COMPONENTS)

Flue & Air Intake

O-Ring

Kit 100371185 Contains:

• O-Rings

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Safety Gloves

WARNING!

This kit shall be installed

by a qualied service

agency in accordance

with the manufacturer’s

instructions and all

applicable codes

and requirements of

the authority having

jurisdiction. The

information in these

instructions must be

followed to minimize the

risk of re or explosion

or to prevent property

damage, personal

injury or death. The

qualied service agency

is responsible for the

proper installation of this

kit.

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Locate the ue exhaust port

and intake air port. See Figure

Air Intake

Port

Flue Exhaust

Port

Screws

Clamp

Figure 209 - Air intake port/Flue exhaust port

locaon

Remove the two (2) self-

tapping screws securing the

intake air and exhaust piping to the

ports. Place the screws aside in a safe

place for reinstallaon. See Figure 1.

Loosen the exhaust port and air

intake clamps.

Disconnect the ue exhaust

pipe from the exhaust port and

air intake pipe from the air intake

port.

Removing the Flue/Intake Air

O-Rings

Remove and dispose of the old

O-rings properly. See Figure 2.

O-Rings

Figure 210 - O-ring locaons

Replacing the Flue/Air Intake

Clamps

Locate the new O-rings

provided in the kit. Place a new

O-ring in the intake air port and the

exhaust port. The O-rings must be

seated fully into the channel of each

port with no distoron or puckering.

Reinstall the ue exhaust pipe

to the exhaust port and air

intake pipe to the air intake port

removed in Step 6.

NOTICE: Before placing the pipes into

the ports make sure they are clean

and free from any debris.

Reinstall the two (2) screws

removed in Step 4. See Figure

Tighten the clamps at the

exhaust and intake air ports to

secure the piping. See Figure 1.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater.

106 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (FLUE & AIR INTAKE COMPONENTS)

Checking for Gas Leaks

Open all hot water xtures in

the house. This will iniate the

call for heat at the water heater.

Check for leaks around the ue

exhaust port. Use a small,

so-bristled brush to apply a hand

dishwashing soap and water mixture

(1 part soap to 15 parts water) or

children’s soap bubbles around the

ue exhaust port. If any leaks are

detected (which will appear as small

bubbles), resecure the connecon and

recheck for leaks.

Close all hot water xtures in

the house once the check is

complete.

Returning the Water Heater to

Operaon

The water heater is now ready

for operaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 107

SERVICE

SERVICE (FLUE & AIR INTAKE COMPONENTS)

108 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (FLUE & AIR INTAKE COMPONENTS)

Flue & Air Intake Clamp

Kit 100371167 Contains:

• Clamps

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Flathead Screwdriver

• Phillips head Screwdriver

• Safety Gloves

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Locate the ue exhaust port

and intake air port. See Figure

211.

Air Intake

Port

Flue Exhaust

Port

Screws

Clamp

Figure 211 - Flue exhaust port and intake air

port locaon

Remove the two (2) screws

securing the intake air and

exhaust piping to the ports. Place the

screws aside in a safe place for

reinstallaon. See Figure 211.

Removing the Flue/Air Intake

Clamps

Using a athead screwdriver

loosen the exhaust port and air

intake clamps.

Disconnect the ue exhaust

pipe from the exhaust port and

air intake pipe from the air intake

port.

Remove the clamps and

dispose of them properly.

Replacing the Flue/Air Intake

Clamps

Locate the new clamps

provided in the kit. Place a new

clamp over the intake air port and the

exhaust port. Note the orientaon of

the clamps. See Figure 210.

Reinstall the ue exhaust pipe

to the exhaust port and air

intake pipe to the air intake port

removed in Step 5.

NOTICE: Before placing the pipes into

the ports make sure they are clean

and free from any debris.

Reinstall the two (2) screws

removed in Step 3.

See Figure 211.

Tighten the clamps at the

exhaust and intake air ports to

secure the piping.

Returning Water Heater to

Operaon

Restore power to the water

heater. The water heater is now

ready for operaon.

Gasket Master Kit

Kit Contains:

• Ignitor & Flame Sensor Gasket (G1)

• Gas Manifold Gasket (G2)

• Burner Gasket (G3)

• Kit Instrucons

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

WARNING!

This kit shall be installed

by a qualied service

agency in accordance

with the manufacturer’s

instructions and all

applicable codes

and requirements of

the authority having

jurisdiction. The

information in these

instructions must be

followed to minimize the

risk of re or explosion

or to prevent property

damage, personal injury

or death. The qualied

service agency is

responsible for the proper

installation of this kit.

Tools and Materials Required:

• Phillips Screwdriver

• Towel or Rag

• Safety Gloves

NOTICE: Use the diagrams (Figure

212) on page 111 to reference the

locaon of gaskets provided in the kit.

Part A

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

The water heater is now ready to

be serviced. Follow the instrucons

below to replace gaskets as needed.

Part B (G1):

Replacing Ignitor and Flame

Sensor Gasket

Disconnect wire from ame

sensor at the ame sensor rod.

Disconnect ignitor wire from the

ignitor assembly.

Remove the four screws

securing the ignitor rod and

ame sensor rod assembly to the

burner assembly. Place screws aside in

a safe place for reinstallaon.

Remove ignitor rod and ame

sensor rod assembly from

burner assembly.

Use a plasc scraper to gently

scrape old insulaon gasket

clean from ignitor rod and ame

sensor rod assembly. Conrm

assembly surface is free of any debris

or leover insulaon.

IMPORTANT! DO NOT gouge or

damage assembly surface when

removing insulaon gasket.

Locate gasket (G1) provided in

the kit. Install new gasket to

ignitor rod and ame sensor rod

assembly.

Install ignitor rod and ame

sensor rod assembly to burner

assembly and connect wires.

Proceed to Part C if no other

gaskets must be replaced.

Part B (G2):

Replacing Gas Manifold Gasket

Locate both green ground wires

aached to gas manifold cover.

Remove the two screws securing the

green ground wires and place them

aside in a safe place for reinstallaon.

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon. Allow UIM and bracket

to rest below water heater for easier

access.

Remove the two screws

securing the ignitor assembly

to the gas manifold. Place screws

aside in a safe place for reinstallaon.

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 109

SERVICE

SERVICE (MASTER KITS)

Disconnect wires and remove

ignitor assembly from gas

manifold. Place assembly aside in a

safe place for reinstallaon.

Remove the eight screws

securing the gas manifold to

the burner assembly. Place screws

aside in a safe place for reinstallaon.

Remove the four screws

securing the gas manifold to

the gas valve. Place screws aside in a

safe place for reinstallaon.

Remove gas manifold from

burner assembly.

Remove the old gas manifold

gasket. Conrm gas manifold

surface is free of any debris.

Locate gasket (G2) provided in

the kit. Install new gasket to gas

manifold.

NOTICE: If also replacing Burner

Assembly Gasket, proceed to Step 8 in

the following secon, Part B (G3).

Install gas manifold to burner

assembly and gas valve.

Install ignitor assembly to gas

manifold. Connect wires.

Secure the User Interface

Module (UIM) and bracket to

water heater. Conrm all electrical

connecons are snug and properly

routed behind bracket.

Secure green ground wires to

gas manifold cover.

Proceed to Part C if no other

gaskets must be replaced.

Part B (G3):

Replacing Burner Assembly

Gasket

Locate both green ground wires

aached to gas manifold cover.

Remove the two screws securing the

green ground wires and place them

aside in a safe place for reinstallaon.

Locate the User Interface

Module (UIM) and bracket. Remove

the four screws securing bracket to

the water heater. Place screws aside

in a safe place for reinstallaon. Allow

UIM and bracket to rest below water

heater for easier access.

Remove the two screws

securing the ignitor assembly

to the gas manifold. Place screws

aside in a safe place for reinstallaon.

Disconnect wires and remove

ignitor assembly from gas

manifold. Place assembly aside in a

safe place for reinstallaon.

Remove the eight screws

securing the gas manifold to

the burner assembly. Place screws

aside in a safe place for reinstallaon.

Remove the four screws

securing the gas manifold to

the gas valve. Place screws aside in a

safe place for reinstallaon.

Remove gas manifold from

burner assembly.

Remove the top nine screws

and the boom two screws

securing burner assembly to heat

exchanger assembly. Place screws

aside in a safe place for reinstallaon.

Remove burner assembly from

heat exchanger assembly.

Use a plasc scraper to gently

scrape old insulaon gasket

clean from burner assembly. Conrm

assembly surface is free of any debris

or leover insulaon.

IMPORTANT! DO NOT gouge or

damage assembly surface when

removing insulaon gasket.

Locate gasket (G3) provided in

the kit. Install new gasket to

burner assembly.

Install burner assembly to heat

exchanger assembly.

Install gas manifold to burner

assembly and gas valve.

Install ignitor assembly to gas

manifold. Connect wires.

Secure the User Interface

Module (UIM) and bracket to

water heater. Conrm all electrical

connecons are snug and properly

routed behind bracket.

Secure green ground wires to

gas manifold cover.

Proceed to Part C if no other

gaskets must be replaced.

Part C

Checking for Gas Leaks

IMPORTANT! DO NOT apply liquids

to any of the electrical connecons

when checking for gas leaks. Use a

towel or rag to protect any electrical

components.

Turn ON the cold water supply

to the water heater at the cold

inlet valve.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater. Open all hot water

xtures in the house. This will iniate

the call for heat at the water heater.

Use code approved methods to

check for leaks around all gas

connecon points. If any leaks are

detected, resecure components and

recheck for leaks.

Once no leaks have been

conrmed, remove towel or rag

from electrical connecons if

necessary.

Close all hot water xtures in

the house once the check is

complete.

Returning Water Heater to

Operaon

Replace the cabinet cover and secure

with the screws previously removed in

Part A, Step 5.

The water heater is now ready for

operaon.

110 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (MASTER KITS)

Ignitor Assembly (2x Screws)

TM Gas Valve

(4x Screws)

Gas Manifold

(8x Screws)

Ignitor &

Flame Sensor

(4x Screws)

Burner Assembly

(9x Top Screws)

(2x Boom Screws)

Green Ground

Wires (2x)

Gas Manifold Front View

TI/TO Gas Valve

(4x Screws)

Figure 212 - Gasket reference guide

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 111

SERVICE

SERVICE (MASTER KITS)

Fastener Master Kit

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

Tools and Materials Required:

• Phillips Screwdriver

• Bucket or Pan

• Towel or Rag

• Safety Gloves

NOTICE: Use the parts diagram (Figure

213) and the table provided on page

113 to reference the locaon of

fasteners provided in the kit.

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

NOTICE: Proceed to Step 5 if replacing

fasteners "D3" and/or "E-G" only.

Replacing these fasteners do not

require a water leak check.

Draining the Water Heater

(Fasteners A-C, D1 & D2 Only)

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Drain the X3®/Bypass Cartridge

and inlet lter. Place a bucket

or pan underneath cartridge and inlet

lter to collect water during removal.

Install cartridge and inlet lter back to

water heater and proceed.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

Locate the User Interface

Module (UIM) and bracket.

Remove the four screws securing

bracket to the water heater. Place

screws aside in a safe place for

reinstallaon. Allow UIM and bracket

to rest below water heater for easier

access.

The water heater is now ready to be

serviced. Replace fasteners as needed.

Once fasteners have been replaced,

proceed to next applicable secon.

Checking for Water Leaks

(Fasteners A-C, D1 & D2 Only)

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Returning Water Heater to

Operaon

Secure the User Interface

Module (UIM) and bracket to

water heater with the four screws

previously removed in Step 7. Conrm

all electrical connecons are snug and

properly routed behind bracket.

Replace the cabinet cover and

secure with the screws

previously removed in Step 5.

Restore power to water heater.

The water heater is now ready for

operaon.

112 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (MASTER KITS)

O-Ring Master Kit

IMPORTANT: Use only factory

authorized replacement parts. DO

NOT USE ELECTRIC SCREWDRIVERS

OR DRILLS, HAND TIGHTEN ALL

SCREWS TO PREVENT OVER

TIGHTENING. If you lack the necessary

skills to properly perform the

installaon, you should not proceed,

but get help from a qualied service

technician.

WARNING!

This kit shall be installed

by a qualied service

agency in accordance

with the manufacturer’s

instructions and all

applicable codes

and requirements of

the authority having

jurisdiction. The

information in these

instructions must be

followed to minimize the

risk of re or explosion

or to prevent property

damage, personal injury

or death. The qualied

service agency is

responsible for the proper

installation of this kit.

NOTICE: Use the parts diagram (Figure

214) and the table provided on page

115 to reference the locaon of

O-rings provided in the kit.

Preparing Water Heater for

Service

Disconnect power to the water

heater by unplugging it or by

turning o the circuit at the breaker

box, as appropriate. The power buon

on the water heater and remote DOES

NOT disconnect power to the water

heater. You must physically disconnect

power to the water heater.

NOTICE: Proceed to Step 6 if replacing

O-ring "B2" only. Replacing this O-ring

does not require a water leak or gas

leak check.

Draining the Water Heater

(O-rings A-F only)

Shut OFF the cold water supply

to the water heater at the cold

inlet valve.

Open all hot water xtures in

the house. When the residual

water ow has ceased, close all hot

water xtures. This will depressurize

the water heater.

Drain the X3®/Bypass Cartridge

and inlet lter. Place a bucket

or pan underneath cartridge and inlet

lter to collect water during removal.

Install cartridge and inlet lter back to

water heater and proceed.

Shung O the Gas Supply

(O-rings G only)

Shut OFF the gas supply to the

water heater at the manual gas

shut o valve.

Accessing Water Heater

Components

Locate the two (2) screws at

the boom of the cabinet

cover. Use a Phillips screwdriver to

remove the screws. Place screws aside

in a safe place for reinstallaon.

Li cover up and away from

cabinet to gain access to the

water heater's internal components.

The water heater is now ready to be

serviced. Replace O-Rings as needed.

NOTICE: Handle with care and verify

lubricant has been applied to O-rings

and O-rings are not dirty or damaged.

Checking for Water Leaks

(O-rings A-F only)

Turn ON the cold water supply

to the water heater at the cold

inlet valve. The system will fully

pressurize and any leaks at water

connecons will be apparent. Correct

any leaks immediately and dry water

heater cabinet with a rag.

Restore power to the water

heater and proceed to the

"Returning Water Heater to

Operaon" secon.

Checking for Gas Leaks

(O-rings G only)

IMPORTANT! DO NOT apply liquids

to any of the electrical connecons

when checking for gas leaks. Use a

towel or rag to protect any electrical

components.

Turn ON the gas supply to the

water heater at the manual gas

shut o valve.

Restore power to the water

heater. Open all hot water

xtures in the house. This will iniate

the call for heat at the water heater.

Use code approved methods to

check for leaks around all gas

connecon points. If any leaks are

detected, resecure components and

recheck for leaks.

Once no leaks have been

conrmed, remove towel or rag

from electrical connecons if

necessary.

Close all hot water xtures in

the house once the check is

complete. Proceed to the following

secon.

Returning Water Heater to

Operaon

Replace the cabinet cover and

secure with the screws

previously removed in Step 6.

The water heater is now ready for

operaon.

114 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

SERVICE

SERVICE (MASTER KITS)

A10

Figure 214 - O-ring reference guide

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 115

SERVICE

SERVICE (MASTER KITS)

Item Part Number

Heater Qty Descripon

A 100371077 10

O-RING, 15.5 x 2.5,

NBR, WATER

B 100371107 4

O-RING, 3.8 x 1.9,

NBR, WATER

C 100390004 3

O-RING, 5.8 x 1.9,

EPN, WATER

D 100371062 1

O-RING, 15.5 x 2.5,

EPDM, WATER

E 100371110 1

O-RING, 2.4 x 1.2,

NBR, WATER

F 100389229 1

O-RING, 17.8 x 2.4,

NBR, WATER

G 100390014 3

O-RING, 25.7 x 3.5,

F4200-70, GAS

116 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

COMPONENTS

Internal Component View (A)

Figure 215 - Internal Component View (A)

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 117

COMPONENTS

Internal Component View (B)

Figure 216 - Internal Component View (B)

118 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

COMPONENTS

External Component View

Figure 217 - External Component View (B)

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 119

COMPONENTS

Internal / External Component List

Table 18: Internal / External Component List

Item Number Component List

1 Water Tube Retainer Clip

2 Freeze Protecon

3 Bypass Water Valve

4 Blower

5 Condensate Trap

6 Main Water Valve

7 Condensate Drain Connecon

8 Heat Exchanger Drain Connecon

9 Pressure Relief Valve

10 Secondary Heat Exchanger

11 Burner

12 Gas Manifold

13 Gas Manifold Cover

14 Condensate Tubing

15 Flame Sensor Rod

16 Ignitor Rod

17 Hot Water Outlet

18 Cold Water Inlet

19 Hi-Limit Switch

20 Primary Heat Exchanger

21 Ignitor Assembly

22 Gas Valve

23 3/4" Gas Connecon

24 Flue & Air Intake O-Ring

25 Flue & Air Intake Clamp

26 Intake Connecon

27 Cartridge Manifold (X3® or Bypass)

28 Bypass Cartridge

29 X3® Cartridge

30 Exhaust Connecon

31 Emission Port Cap

32 Outdoor Vent Cap*

33 Printed Circuit Board (PCB)

34 Front Cover

35 User Interface Module (UIM) Cover*

36 User Interface Module (UIM)

*Components for outdoor applicaons only.

COMPONENTS

Electrical Wiring Diagram

HEATING STICKER

ANTI-FREEZE

SWITCH

10W

25W

10W10W10W

10W10W25W25W

120 VAC POWER

L N

CN1

EARTH

CN2

EARTH

CN0

MAGNETIC

RING

120 VAC

POWER

CN6

MAIN

WATER

VALVE

BYPASS

WATER

VALVE

CN7

PROPORTIONAL

VALVE

THERMAL FUSEHIGH LIMIT

CON2

MAIN VALVE

VALVE C

VALVE B

VALVE A

VALVE D

24V

IGNITOR

ROD

INGI

GND

VAL_D

VAL_C

VAL_B

VAL_A

MAIN_V

24V

24V_IN

24V_OUT

P_VAL-

P_VAL+

24V

GROUND

FLAME1

GROUND

FLAME

SENSOR

CN5

CASCADE

CN8CN9

CN4

FAN

DISPLAY

FERRITE

BEAD

(OR OTHER COMMUNCATION

EQUIPMENT)

RESERVED

FERRITE

BEAD

CON1

LIQUID

LEVEL

SWITCH

INLET WATER

TEMPERATURE

OUTLET WATER

TEMPERATURE

SMOKE

TEMPERATURE

HEAT EXCHANGER

TEMPERATURE

WATER FLOW

SENSOR

(OR OTHER COMMUNCATION

EQUIPMENT)

Figure 218 - Electrical wiring diagram

120 • Residenal Standard Condensing Gas Tankless Water Heater Service Handbook

DIAGRAMS

Thermistor Resistance Vs Temperature Charts

20 40 60 80 100 120 140 160 180 200 220 240

Resistance (kΩ)

Temperature (°F)

Resistance Values of Thermistors (Fahrenheit)

Figure 219 - Thermistor value diagram (Fahrenheit)

0 20 40 60 80 100 120

Resistance (kΩ)

Temperature (°C)

Resistance Values of Thermistors (Celsius)

Figure 220 - Thermistor value diagram (Celsius)

Residenal Standard Condensing Gas Tankless Water Heater Service Handbook • 121

DIAGRAMS

Lochinvar LTM-199X3-N 100 XCalibur® Standard Condensing Ultra-Low NOx 199,000 BTU Natural Gas Tankless Water Heater with X3® Scale Prevention Technology

Product's Documents

Manual - XCalibur® Standard Condensing Tankless Water Heater Service Handbook

Specifications

Lochinvar LTM-199X3-N 100 Questions and Answers

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