AO Smith ATI-310U ProLine XE Ultra-Low NOx Indoor 190,000 User Manual

Gas Tankless Water Heater

Suitable for combination potable water heating

and space-heating

Please refer to local codes for space-heating compliance.

FEATURING

 • ENDLESSHOTWATER

 • ON-DEMANDUSAGE

 • COMPACT,SPACESAVING

 • ENERGYCONSERVATION

 • COMPUTERIZEDSAFETY

 • NOPILOTLIGHT

 • ComplieswithSCAQMDRule

1146.2forNOxemissionsrequire-

mentof14ng/Jor20ppm

 • FIELDGASCONVERTIBLE

 • EASY-LINKSYSTEMAND

MULTI-UNITSYSTEM

(510U (AT-D3U-IN/OS) only)

Ifyouhaveanyquestions,please

callorwriteto:

500TennesseeWaltzParkway

AshlandCity,TN37015

TollFree:1-877-737-2840

On-Demand Water Heater

Installation Manual and Owner’s Guide

- Do not store or use gasoline or other

flammablevaporsandliquidsinthevicinity

ofthisoranyotherappliance.

- WHATTODOIFYOUSMELLGAS

 • Donottrytolightanyappliance.

 • Donottouchanyelectricswitch,donot

useanyphoneinyourbuilding.

 • Immediatelycallyourgassupplierfrom

aneighbor'sphone.Followthegas

supplier'sinstructions.

 • Ifyoucannotreachyourgassupplier,call

thefiredepartment.

- Installation and service must be performed

byaqualifiedinstaller,serviceagencyorthe

gassupplier.

WARNING

If the information in these

instructions is not followed

exactly,afireorexplosionmay

resultcausingpropertydamage,

personalinjuryordeath.

ANSI Z21.10.3 ・ CSA 4.3

510U (AT-D3U-IN/OS)

only

Models

• 110U Outdoor (AT-KJr3U-OS)

• 310U Outdoor (AT-K5U-OS)

• 510U Outdoor (AT-D3U-OS)

• 110U Indoor (AT-KJr3U-IN)

• 310U Indoor (AT-K5U-IN)

• 510U Indoor (AT-D3U-IN)

Series 200

2 Page

CONTENTS

Installation Manual

SPECIFICATIONS .............................................4

INTRODUCTION ..........................................5

SAFETY GUIDELINES.....................................6

SAFETY DEFINITION ....................................6

GENERAL ......................................................6

INSTALLATION ................................................7

GENERAL ......................................................7

CLEARANCES ...............................................9

INCLUDED ACCESSORIES ............................9

OPTIONAL ITEMS ........................................ 9

WARNING FOR INSTALLATIONS ...............11

HIGH-ALTITUDE INSTALLATIONS .............12

VENTING INSTRUCTIONS .........................13

General .....................................................13

Combustion Air Supply .............................15

Vent length and No. of Elbows .................19

DIP switch settings for Vent length ..........20

Clearances for sidewall terminations .......23

Clearances for rooftop terminations ........23

Clearances for multiple sidewall

terminations .............................................24

Clearances for multiple rooftop

terminations .............................................24

Vent termination clearances ....................25

GAS SUPPLY AND GAS PIPE SIZING .........26

General .....................................................26

Gas connections .......................................26

Natural Gas Supply Piping ........................27

Propane (LP) Supply Piping .......................27

Measuring inlet gas pressure ...................28

WATER CONNECTIONS .............................28

Pressure relief valve .................................29

ELECTRICAL CONNECTIONS .....................29

TEMPERATURE REMOTE CONTROLLER .....30

Included accessories .................................30

Installation ................................................30

EASY-LINK SYSTEM .........................................32

Easy link connection procedures ..............32

MULTI-UNIT SYSTEM ......................................34

APPLICATIONS ..............................................35

SPACE HEATING APPLICATIONS ............... 35

RECIRCULATION ........................................35

DUAL-PURPOSE HOT WATER HEATING ...... 36

INITIAL OPERATION .....................................37

Owner's Guide

OPERATING SAFETY .....................................39

NORMAL OPERATION ..................................41

BUILT-IN CONTROLLER

AND REMOTE CONTROLLER ..................41

GENERAL ....................................................41

TEMPERATURE SETTINGS ........................42

TEMPERATURE SETTINGS ON THE PCB ........44

FLOW .......................................................... 45

FREEZE PROTECTION SYSTEM ................. 45

MAINTENANCE AND SERVICE ................. 46

UNIT DRAINING AND FILTER CLEANING .......46

TROUBLESHOOTING .....................................47

GENERAL ....................................................47

ERROR CODES ...........................................49

COMPONENTS DIAGRAM ............................53

PARTS LIST ....................................................57

OUTPUT TEMPERATURE CHART ..................60

LIMITED WARRANTY ....................................61

Contents

3 Page

Installaon Manual

Installation Manual

CONGRATULATIONS

Congratulations and thank you for choosing our tankless water heater.

Before use, we recommend that you read through this installation

manual carefully. Please refer to the back of the manual for details

about the warranty. Keep this manual for future reference.

If you need an additional manual, contact the manufacturer or your

local distributor. When you call, please tell us the product name and

the serial number of your unit written on the rating plate of the water

heater.

4 Page

Model

110U

Indoor

(AT-KJr3U-

IN)

110U

Outdoor

(AT-KJr3U-

OS)

310U

Indoor

(AT-K5U-

IN)

310U

Outdoor

(AT-K5U-

OS)

510U

Indoor

(AT-D3U-

IN)

510U

Outdoor

(AT-D3U-

OS)

Natural Gas Input

(Operating Range)

BTU/h

Min.: 15,000

Max.: 140,000

Min.: 15,000

Max.: 190,000

Min.: 15,000

Max.: 199,000

Gas Connection 3/4" NPT

Water Connections 3/4" NPT

Water Pressure*

psi

(Mpa)

15 - 150 (0.1 - 1)

Natural gas

Inlet Pressure

" W.C.

(kPa)

Min. 4.0 (1.00)

Max. 10.5 (2.61)

Weight lbs. (kg) 37.5 (17.0) 39.7 (18.0)

Dimensions

Indoor

H 20.5 x W 13.8 x D 9.1 (Inch)

H 520 x W 351 x D 231 (mm)

Outdoor

H 20.5 x W 13.8 x D 8.5 (Inch)

H 520 x W 351 x D 216 (mm)

Ignition Electric Ignition

Electric

Supply VAC / Hz 120 / 60

Consumption

Operation W / A 54 / 0.64 79 / 0.99 82 / 1.02

Standby W / A 2 / 0.06 2 / 0.06 3 / 0.07

Freeze-

Protection

W / A 96 / 0.82 96 / 0.82 97 / 0.82

SPECIFICATIONS

*Maximum flow may need water pressure equal to or above 40 psi.

NOTE:

• Check the rating plate to ensure this product matches your specifications.

• The manufacturer reserves the right to discontinue, or change at any time, specifications or designs

without notice and without incurring obligations.

Specicaons

Installaon Manual

5 Page

INTRODUCTION

• This manual provides information necessary for the installation, operation, and maintenance

of the water heater.

• The model description is listed on the rating plate which is attached to the side panel of the

water heater.

• Please read all installation instructions completely before installing this product.

• If you have any problems or questions regarding this equipment, consult the manufacturer or

its local representative.

• This appliance is an on-demand, tankless water heater. It is designed to efficiently supply

endless hot water for your needs.

• The 110U Indoor (AT-KJr3U-IN), 310U Indoor (AT-K5U-IN) and 510U Indoor (AT-D3U-IN) models

are only to be installed indoors. The 110U Outdoor (AT-KJr3U-OS), 310U Outdoor (AT-K5U-OS)

and 510U Outdoor (AT-D3U-OS) models are only to be installed outdoors.

• The principle behind tankless water heaters is simple:

Burners

Hot water xture

Exhaust vent

Heat exchanger

Gas valves

Fan motor

Flow adjustment valve

Computer board

Thermistor

Cold water inlet

Hot water outlet

Gas inlet

Thermistor

Burners

Flow sensor

Igniter

Intake vent

*This diagram illustrates tankless water heater design concepts only and does not accurately represent

the water heater’s physical description.

1. A hot water fixture is turned on.

2. Water flows through the heater.

3. The water flow sensor detects the water flow.

4. The computer initiates the fan motor and gas valve to let gas flow through the heater and sends a

signal to the igniter to create an ignition spark.

5. The gas ignites and flames appear within the burner chamber.

6. Water is heated as it flows through the heat exchanger.

7. Using thermistors to measure temperatures throughout the water heater, the computer modulates

the gas and water valves to ensure proper output water temperature and hot water outflows.

8. When the fixture is turned off, the unit shuts down.

Introducon

Installaon Manual

6 Page

SAFETY GUIDELINES

SAFETY DEFINITION

GENERAL

1. Follow all local codes, or in the absence of local codes, follow the current edition of the National Fuel Gas Code:

ANSI Z223.1/NFPA 54 in the USA or B149.1 Natural Gas and Propane Installation code in Canada.

2. Properly ground the unit in accordance with all local codes, or in the absence of local codes, with the current

edition of the National Electrical Code: ANSI/NFPA 70 in the USA or CSA standard C22.1 Canadian Electrical

Code Part 1 in Canada.

3. Carefully plan where you intend to install the water heater. Please ensure:

• Your water heater will have enough combustion air and proper ventilation.

• Locate your heater where water leakage will not damage surrounding areas. (Please refer to p. 8.)

4. Check the rating plate for the correct GAS TYPE, GAS PRESSURE, WATER PRESSURE and ELECTRIC RATING. If this

unit does not match your requirements, do not install and consult with the manufacturer. The water heater is

configured only for use with Natural Gas at the factory. If the appliance is used with propane gas, conversion to

propane gas with an included conversion kit (LP Conversion Kit: 100270585) is required. The conversion must

be done by a qualified service agent or a gas utility serviceman in accordance with this instruction and all codes

and requirements of the authority having jurisdiction. Failure to follow instructions could result in serious injury

or property damage. The agent performing this work assumes responsibility for this conversion. (Refer to the

gas conversion leaflet.)

5. If any problem should occur, turn off all hot water fixtures and turn off the gas. Then call a trained technician

or the Gas Company or the manufacturer.

Safety Guidelines

Installaon Manual

WARNING

Indicates an imminently hazardous situation which, if not avoided, could result

in death or serious injury.

CAUTION

Indicates an imminently hazardous situation which, if not avoided, could result

in minor or moderate injury.

Indicates an imminently hazardous situation which, if not avoided, will result in

death or serious injury.

DANGER

Indicates information considered important but not hazard related.

WARNING

• Water temperatures over 125 °F (52 °C) can cause severe burns instantly or death from

scalding. The water temperature is set at 120 °F (50 °C) from the factory to minimize any

scalding risk. Before bathing or showering, always check the water temperature.

• Do not store or use gasoline or other flammables, vapors, or liquids in the vicinity of this appliance.

• Do not reverse the water and/or gas connections as this will damage the gas valves and can

cause severe injury or death. Follow the diagram on p. 28 when installing your water heater.

• The conversion to propane must be done by a qualified service agent or a gas utility

serviceman in accordance with the gas conversion instructions and all codes and

requirements of the authority having jurisdiction. Failure to follow instructions could

result in serious injury or property damage. The qualified agent performing this work

assumes responsibility for this conversion.

• Do not use this appliance if any part has been under water. Immediately contact a

qualified installer or service agency to replace a flooded water heater. Do not attempt

to repair the unit! It must be replaced!

• Do not disconnect the electrical supply if the ambient temperature will drop below

freezing. The Freeze Protection System only works if the unit has electrical power. The

warranty will not be covered if the heat exchanger is damaged due to freezing. For more

information, refer to Freeze Protection System on p. 45.

NOTICE

7 Page

INSTALLATION

GENERAL

1. Follow all local codes, or in the absence of local codes, follow the current edition of the National Fuel

Gas Code: ANSI Z223.1/NFPA 54 in the USA or B149.1 Natural Gas and Propane Installation Code in

Canada.

2. All gas water heaters require careful and correct installation to ensure safe and efficient operation.

This manual must be followed exactly. Read the “Safety Guidelines” section.

3. The manifold gas pressure is preset at the factory. It is computer controlled and should not need

adjustment.

4. Maintain proper space for servicing. Install the unit so that it can be connected or removed easily.

Refer to the "Clearances" section on p. 9 for proper clearances.

5. The water heater must be installed in a location where the proper amount of combustible air will be

available to it at all times without obstructions.

6. The electrical connection requires a means of disconnection, to terminate power to the water heater.

This is necessary for servicing and safety purposes.

7. Do not install the unit where the exhaust vent is pointing into any opening in a building or where the

noise may disturb your neighbors. Ensure that the vent termination meets the minimum distance

requirements set by code, including minimum clearances from doorways or openings. (Refer to pp.24

and 25.)

8. Particles from flour, aerosols, and other contaminants may clog the air vent, build up and reduce

the functions of the rotating fan, cause improper burning of the gas, or cause damage to the water

heater. Regularly ensure that the area around the unit is dust- or debris-free. Regular maintenance is

recommended for these types of environments. Direct Venting is recommended.

9. For 110U Indoor (AT-KJr3U-IN), 310U Indoor (AT-K5U-IN) and 510U Indoor (AT-D3U-IN) models:

• If the water heater is used as a direct-vent appliance, the unit requires a 3 in. (76 mm)

combustible air supply pipe. The intake pipe must be sealed airtight. Refer to "VENTING

INSTRUCTIONS" on p.13 for more detail.

• Terminating the venting through a sidewall is recommended for the direct-vent system.

• Running the exhaust vent and the intake pipe parallel is recommended.

• Terminating the exhaust and intake on the same wall/surface is recommended. Terminating in

the same pressure zone allows for pressure balancing, which prevents nuisance shutdowns.

• Only install the water heater in a heated area where below freezing temperatures cannot occur.

The warranty does not cover damage caused by freezing.

• The water heater must be securely mounted to a wall or other suitable structure.

10. The 110U Outdoor (AT-KJr3U-OS), 310U Outdoor (AT-K5U-OS) and 510U Outdoor (AT-D3U-OS) models

are only to be installed outdoors and only in an area with mild, temperate climates. The Outdoor

model shall be wall mounted, mounted on a stand, or installed in an approved recess box. Locate the

Outdoor model in a open, unroofed area and maintain the minimum clearances. (Refer to p.11.)

Installaon

Installaon Manual

8 Page

• Installation and service must be performed by a qualified installer (for example,

a licensed plumber or gas fitter). Otherwise, the warranty will be void.

• The installer (licensed professional) is responsible for the correct installation of

the water heater and for compliance with all national, state / provincial, and local

codes.

• The manufacturer does not recommend installing the water heater in a pit or

location where gas and water can accumulate.

• Do not have the vent terminal pointing toward any operating window, door, or

opening into a building.

• Do not install next to any source of airborne debris, such as a clothes dryer, that

can cause debris to be trapped inside the combustion chamber, unless the system

is direct-vented.

• The manufacturer does not suggest installing the water heater in an attic due to

safety issues. If you install the water heater in an attic:

• Make sure the unit will have enough combustion air and proper ventilation.

• Keep the area around the water heater and its termination clean. When dust

collects on the flame sensor, the water heater will shut down and produce an

error code.

• Place the unit for easy access for service and maintenance.

• A drain pan, or other means of protection against water damage, is

recommended to be installed under the water heater in case of leaks. The

manufacturer is not responsible for damage due to water leaks.

WARNING

• The warranty will not cover damage caused by water quality.

• Only potable water can be used with this water heater. Do not introduce pool

or spa water, or any chemically treated water into the water heater.

• Water hardness levels must not exceed 7 grains per gallon (120 ppm) for

single family domestic applications or more than 4 grains per gallon (70 ppm)

for all other types of applications. Water hardness leads to scale formation

and may affect / damage the water heater. Hard water scaling must be

avoided or controlled by proper water treatment.

• Water pH levels must be between 6.5 and 8.5

• Well water must be treated.

• Do not install the unit where water, debris, or flammable vapors may get into the

flue terminal.

• The manufacturer recommends direct venting when the water heater is installed

in beauty salons, dry cleaners or any other locations in which such chemicals

are present in the air. Some chemicals used in beauty salons or dry cleaners may

affect the flame sensor. In such cases, the water heater may not work properly.

• Although the water heater is designed to operate with minimal sound, the

manufacturer does not recommend installing the unit on a wall adjacent to a

bedroom, or a room that is intended for quiet study or meditation, etc.

• Locate your heater close to a drain where water leakage will not do damage to

surrounding areas. As with any water heating appliance, the potential for leakage

at some time in the life of the product does exist. The manufacturer will not be

responsible for any water damage that may occur. If you install a drain pan under

the unit, ensure that it will not restrict the combustion air flow.

CAUTION

Installaon

Installaon Manual

9 Page

Top

Back

Boom

Side

Front

Maintain all clearances around

the water heater.

CLEARANCES

OPTIONAL ITEMS

Model

110U

Indoor

(AT-KJr3U-IN)

110U

Outdoor

(AT-KJr3U-OS)

310U

Indoor

(AT-K5U-IN)

310U

Outdoor

(AT-K5U-OS)

510U

Indoor

(AT-D3U-IN)

510U

Outdoor

(AT-D3U-OS)

4” Backflow preventer and F-F adaptor

✓ ✓ ✓

4" Universal Appliance Adaptor, F-F adaptor,

backflow preventer, condensate drain trap

✓ ✓ ✓

Pipe cover

✓ ✓ ✓ ✓ ✓ ✓

Recess box (Retrofit)

✓ ✓ ✓

Recess box (New construction)

✓ ✓ ✓

Sidewall vent terminator (Hood) and

Wall thimble

✓ ✓ ✓

Sidewall vent terminator (Round) and

Wall thimble

✓ ✓ ✓

Direct-vent concentric

termination

✓ ✓ ✓

6. Remote controller

✓

Included

✓

Included

✓

Included

Installaon

Installaon Manual

INCLUDED ACCESSORIES

Installation

manual

and Owner’s

guide

Temperature remote

controller kit

(Outdoor model only)

Communication cable

510U

(AT-D3U-IN/OS)only

LP Conversion Kit (100270585)

Qty: 1

9009069005

(TM-RE42)

Qty: 1

Manifold aachment : 2 Small / 1 Large

Manifold gasket (319143-581): 1

Gas conversion scker : 1

Gas conversion instrucon : 1

Spare Screw : 2

(319143-581)

(320273-585)

Model Top Bottom Front Back Sides

110U Indoor (AT-KJr3U-IN)*

310U Indoor (AT-K5U-IN)*

510U Indoor (AT-D3U-IN)*

12 in.

(305 mm)

12 in.

(305 mm)

4 in.**

(102 mm)

1.0 in.

(25 mm)

3 in.

(76 mm)

110U Outdoor (AT-KJr3U-OS)***

310U Outdoor (AT-K5U-OS)***

510U Outdoor (AT-D3U-OS)***

36 in.

(914 mm)

12 in.

(305 mm)

24 in.

(610 mm)

1.0 in.

(25 mm)

3 in.

(76 mm)

*Standard indoor installations and direct-vent indoor installations have the same clearances.

**24 inches recommended for maintenance.

***For the multiple installation of outdoor models, refer to the above clearances.

10 Page

The pipe cover protects

the plumbing pipes to

the water heater. It is

fixed to the bottom of

the water heater, so it

hides the plumbing and

improves the appearance

of the installation.

3. Recess box: It allows for “clean” installations. The water heater fits inside

the recess box, which hides and protects the whole water heater and plumbing.

The recess box will fit between most wall studs.

1. 4” Backflow preventer and Female-female adaptor

9007996005

9008146004

100266729

100266730

It prevents the backflow of air through the exhaust vent. This

helps prevent harmful exhaust gases from entering the home, as

well as helping to prevent the unit from freezing in areas where

cold air can be blown or drawn into the exhaust system.

Install this adaptor in accordance with the installation instructions

that are packaged with the adaptor and any applicable codes.

9007996005 (4” Backflow preventer and F-F adaptor): Must be installed in the vertical position.

9008146005 (4" Universal Appliance Adaptor, F-F adaptor, backflow preventer, condensate drain trap): Must be installed in the

vertical position on the heater's flue collar.

4. Sidewall vent terminator (Hood) and Wall thimble:

Sidewall vent termination (Round) and Wall thimble:

This component is used to terminate direct-vent (sealed

combustion) systems with indoor models that require a

3 in. intake and a 4 in. exhaust. This concentric termination provides the convenience

of only having to make one penetration through a sidewall instead of two separate

penetrations for the intake and exhaust piping. The termination includes a bird

screen, restricting small animals, pests, and foreign objects from entering into the

vent system. This sidewall termination is available in two different sizes to cover a

wide range of wall thicknesses. For different wall thicknesses,there are two ranges

of lengths available. (Refer to the venting manufacturer's specifications for details.)

Installaon

Installaon Manual

Covering wall thicknesses Part#

Terminator Hood 9007999005

Wall Thimble 4 - 7 in. 9008345005

Wall Thimble 5 - 10 in. 9008346005

Termination + Thimble 4 - 7 in. 9008004005

Termination + Thimble 5 - 10 in. 9008005005

Covering wall thicknesses Part#

Termination 9008899005

Wall Thimble 9008898005

Termination + Thimble 9008900005

2. Pipe cover: 9007670005 (TK-PC01)

Covering wall thicknesses Part#

5.0 – 10.0 in. 9008147005

12.0 – 18.0 in. 9008148005

5. Direct-vent concentric termination:

The terminator hood and wall thimble can be used to vent through a wall. These terminations are special stainless steel

vents for gas appliances and are listed as Category II, III and IV. For different wall thicknesses, there are two ranges of lengths

available. (Refer to the NovaVent brochure for details.) Install these vent terminations in accordance with their installation

instructions and any applicable local codes.

Refer to p. 21 regarding the DIP switch settings for the termination.

Wall Thimble

Terminator Hood

6. Remote controller:

9009069005 (TM-RE42)

9008900005 (Termination + Thimble)

Outdoor recess box

for retrofic applications-

no flange

Outdoor recess box

for new construction

applications-with flange

9008899005

(Termination)

9008898005

(Wall Thimble)

11 Page

WARNING FOR INSTALLATIONS

FOR YOUR SAFETY, READ BEFORE INSTALLATION:

Do not install the heater where water, debris or

flammable vapors may get into the flue terminal.

This may cause damage to the heater and void the

warranty.

Do not have the vent terminal pointing toward

any opening into a building. Do not locate your

water heater in a pit or location where gas and

water can accumulate.

Do not install this water heater under an

overhang less than 3 ft. (914 mm) from its top

or eaves. The area under an overhang must be

open to three sides (Outdoor models only).

Do not install the water heater direct vent ter-

minator within 1 ft. (30 cm) in the USA of any air

intake or building opening, and within 3 ft. (91

cm) in Canada of any air intake or building open-

ing ( Refer to pp. 24 and 25.).

Do not install next to a dryer or any source

of airborne debris that can be trapped inside

the combustion chamber, unless the system

is direct-vented. The air intake must maintain

a safe distance from the dryer's exhaust vent.

This will help to prevent lint from being drawn

into the water heater's air intake.

Prohibited

1 . (30 cm) min. USA

3 . (91 cm) min. Canada

1 . (30 cm) min. USA

3 . (91 cm) min. Canada

1 . (30 cm) min. USA

3 . (91 cm) min. Canada

12-inches (30.48 cm) above grade

or ancipated snow level

Ancipated snow level

3 ft.

(914 mm)

Installaon

Installaon Manual

Water heater vent terminator must be at least 2

ft. (610 mm) away from an inside corner for both

outdoor installation, indoor single vent, or direct-

vent installation.

Inside

Corner

2 ft.

(610 mm)

12 Page

Bank of DIP switches

110U (AT-KJr3U-IN/OS) and 310U (AT-K5U-IN/OS)

Computer board

NOTE: The dark squares indicate the correct DIP switch positions.

Lower bank of DIP switches

510U (AT-D3U-IN/OS)

Computer board

Installaon

Installaon Manual

Outdoor models

0 to 2,000 ft.

(0 to 610 m)

(DEFAULT)

2,001 to

4,000 ft.

(611 to 1,219 m)

4,001 to

6,000 ft.

(1,220 to 1,829 m)

110U (AT-KJr3U) and

310U (AT-K5U) models

OFF

1 2 3 4 5 6 7 8 9 10

No. 3 : OFF

No. 4 : OFF

No. 5 : OFF

OFF

1 2 3 4 5 6 7 8 9 10

No. 3 : OFF

No. 4 : OFF

No. 5 : ON

OFF

1 2 3 4 5 6 7 8 9 10

No. 3 : ON

No. 4 : OFF

No. 5 : ON

510U (AT-D3U) model

(Lower bank of

DIP switches)

OFF

1 2 3 4 5 6

No. 2 : OFF

No. 3 : OFF

No. 4 : OFF

OFF

1 2 3 4 5 6

No. 2 : OFF

No. 3 : OFF

No. 4 : ON

OFF

1 2 3 4 5 6

No. 2 : ON

No. 3 : OFF

No. 4 : ON

Indoor models

0 to 2,000 ft.

(0 to 610 m)

(DEFAULT)

2,001 to

3,000 ft.

(611 to 914 m)

3,001 to

5,000 ft.

(915 to 1,524 m)

5,001 to

7,500 ft.

(1,525 to 2,286 m)

7,501 to

10,100 ft.

(2,287 to 3,078 m)

110U (AT-KJr3U) and

310U (AT-K5U) models

OFF

1 2 3 4 5 6 7 8 9 10

No. 3 : OFF

No. 4 : OFF

No. 5 : OFF

OFF

1 2 3 4 5 6 7 8 9 10

No. 3 : OFF

No. 4 : ON

No. 5 : OFF

OFF

1 2 3 4 5 6 7 8 9 10

No. 3 : OFF

No. 4 : OFF

No. 5 : ON

OFF

1 2 3 4 5 6 7 8 9 10

No. 3 : OFF

No. 4 : ON

No. 5 : ON

OFF

1 2 3 4 5 6 7 8 9 10

No. 3 : ON

No. 4 : ON

No. 5 : ON

510U (AT-D3U) model

(Lower bank of

DIP switches)

OFF

1 2 3 4 5 6

No. 2 : OFF

No. 3 : OFF

No. 4 : OFF

OFF

1 2 3 4 5 6

No. 2 : OFF

No. 3 : ON

No. 4 : OFF

OFF

1 2 3 4 5 6

No. 2 : OFF

No. 3 : OFF

No. 4 : ON

OFF

1 2 3 4 5 6

No. 2 : OFF

No. 3 : ON

No. 4 : ON

OFF

1 2 3 4 5 6

No. 2 : ON

No. 3 : ON

No. 4 : ON

Altitude

DIP switches

Installation altitude

The maximum certified or

allowable installed altitude

is 10,100 ft. (3,078 m) for

indoor models and 6,000

ft. (1,829 m) for outdoor

models.

Altitude

DIP switches

HIGH-ALTITUDE INSTALLATIONS

Check the elevation where your water heater is installed. Set your DIP switches according to altitude as

shown below.

13 Page

VENTING INSTRUCTIONS

For indoor models

-General-

• Improper venting of this appliance can result in excessive levels of carbon

monoxide which can result in severe personal injury or death.

• Improper installation can cause nausea or asphyxiation, severe injury or death

from carbon monoxide and flue gases poisoning. Improper installation will void

product warranty.

WARNING

When installing the vent system, all applicable national and local codes must be

followed. If you install thimbles, fire stops or other protective devices and they

penetrate any combustible or noncombustible construction, be sure to follow all

applicable national and local codes.

CAUTION

The water heater must be vented in accordance with the section “Venting of Equipment" of the current

edition of the National Fuel Gas Code: ANSI Z223.1/NFPA 54, as well as applicable local building codes.

The manufacturer recommends NovaVENT™ or Z-Vent® category III, single wall, stainless steel venting.

See "Approved Category III, Single Wall, Stainless Steel Venting Suppliers and Part Numbers" on page 14.

General rules for air intake:

The water heater can obtain its combustion air from the space that it is installed in or it can be direct

vented.

• The air intake can use 3" PVC (solid core), CPVC (solid core), ABS, or category III vent.

• Use of cellular core PVC (ASTM F891), cellular core CPVC, or Radel® (polyphenylsulfone) in non-

metallic venting systems is prohibited. Covering non-metallic vent pipe and fittings with thermal

insulation is prohibited.

• Ensure that the installation location has sufficient, clean combustion air. If unsure, direct vent the

heater or refer to the Combustion Air Supply section below.

Direct venting installation:

• The maximum length of intake air piping must not exceed 60 ft. (18.3 m). Deduct 5 ft. (1.5 m) for

each 90° elbow or 2.5 ft (0.76 m) for each 45° elbow used in the venting system. Two 45° elbows

when connected together are equivalent to one 90° elbow. Refer to the tables on p. 19.

• When the horizontal air intake exceeds more then 5 ft., support the pipe every 3 ft. with pipe

hangers.

• Vertical air intake pipe must be supported with pipe hangers. Ensure that the weight of the pipe

is not carried by the water heater.

Combustion air from the room:

• Install a 3" elbow into the air intake collar.

General rules for venting water heaters are:

• Place the water heater as close as possible to the vent termination.

• The vent collar of the water heater must be fastened directly to an unobstructed vent pipe.

• Do not weld the vent pipe to the water heater’s vent collar.

• Do not cut or alter the shape of the vent collar of the unit.

• The vent must be easily removable from the top of the water heater for normal service and

inspection of the unit and vent system.

• The water heater vent must not be connected to any other gas appliance or vent stack.

• Avoid using an oversized vent pipe or using extremely long runs of pipe.

• For rooftop venting, a rain cap or other form of termination that prevents rain water from

entering into the water heater must be installed.

• Do not common vent or connect any vent from other appliances to the water heater vent.

Installaon

Installaon Manual

14 Page

• A condensate collector is required for horizontal and/or vertical vent runs exceeding 5 ft. of

equivalent length (not including sidewall terminatons).

• A backflow preventor should be installed in the exhaust when the heater is installed in climates

subject to freezing temperatures.

General rules for vent terminations:

• Avoid locating the water heater vent termination near any air intake devices. These fans can

pick up the exhaust flue products from the water heater and return them to the building. This

can create a health hazard.

• Locate the vent termination so that it cannot be blocked by any debris, at any time. Most codes

require that the termination must be at least 12 in. (305 mm) above grade and anticipated snow

level, but the installer may determine if it should be higher depending on the job site condition

and applicable codes.

• A proper sidewall termination is required when the water heater is vented through a sidewall.

• Refer to the following pages for exhaust termination and air inlet clearances.

Approved Category III, Single Wall, Stainless Steel Venting Suppliers and Part Numbers

WARNING! Do not mix parts or fittings of different material types, and do not mix pipe, fittings, or

joining methods from different manufacturers. Combustion exhaust can contain carbon monoxide and

must be properly vented outside. Breathing abnormal amounts of carbon monoxide can result in seri-

ous injury or death.

Description

Heater Vent Kits

Z-FLEX®

NovaVENT™ Z-VENT™

4" Straight pipe - 6" length

9007987005 2NVP4.5 2SVEPWCF0406

4" Straight pipe - 12" length

9007986005 2NVP41 2SVEPWCF0401

4" Straight pipe - 24" length

9007984005 2NVP42 2SVEPWCF0402

4" Straight pipe - 36" length

9007983005 2NVP43 2SVEPWCF0403

4" Straight pipe - 48" length

9007982005 2NVP44 2SVEPWCF0404

4" Adjustable straight pipe - 10"-18" adjustability

9007985005 2NVAL4 2SVSPA04

4" 45 degree elbow

9007981005 2NVE445 2SVEEWCF0445

4" 90 degree elbow

9007980005 2NVE490 2SVEEWCF0490

4" Sidewall termination (4"Termination Hood)

9007999005 2NVHTX4 2SVSHTX04

4" Vent termination tee

9008144005 2NVTT4 2SVSTTF04

4" Rain Cap

9007995005 2NVRC4 2SVSRCF04

4" Extreme weather rain cap

9008145005 2NVWC4 2SVSHRC04

4" Horizontal drain tee

9007994005 2NVHD4 2SVEDWCF04

4" Vertical drain tee

9007993005 2NVVD4 2SVEVDP04

4" wall thimble length 4"-7" wall thickness

9008345005 2NVWT4 2SVSWTF04

4" wall thimble length 5"-10" wall thickness

9008346005 2NVWT4L 2SVSWTEF04

4" 3-in-1 adaptor (F-F adaptor, condensate

drain, & back-flow preventer)

9008146005 2NVBFA4 2SVBFDPA04

4" F-F adaptor

9007979005 2NVAFF4 2SVEEWCF0445

4" Backflow preventer w/ F-F adaptor

9007996005 2NVBFU4 2ZVB04

4" exhaust / 3" intake DV concentric termina-

tion - 5"-10" adjustability

9008147005 2NVHTC43S 2SVSHTC43S

4" exhaust / 3" intake DV concentric termina-

tion - 12"-18" adjustability

9008148005 2NVHTC43 2SVSHTC43

4" Sidewall termination, adjustable pipe

9008899005 2NVBV4 n/a

4" Wall Thimble, 3"-6" wall thickness

9008898005 2NVBT4 n/a

15 Page

-Combuson Air Supply-

• This gas water heater requires an adequate source of clean air for combustion

and ventilation. Without sufficient air, your water heater may not operate

properly and may emit excessive and abnormal amounts of carbon monoxide

which may result in carbon monoxide poisoning or death.

WARNING

Before installing the water heater, you must determine the amount of air needed to supply this water

heater and any other gas appliances in the same area and provide adequate air for combuson and venla-

on. Consult a qualied person if you’re unsure of the proper way to supply air to your water heater.

Before beginning

Calculate total BTU/h rang of all appliances.

To calculate the combuson air and venlaon required, add up the total BTU/h rangs of all gas burn-

ing appliances (e.g., water heaters, furnaces, clothes dryers) in the same area. Do not include appliances

that are direct vented. Refer to the following example.

Your water heater’s BTU/h rating is on the rating plate. The BTU/h ratings should be on the other

appliances’ rating plates. If you have trouble determining the BTU/h ratings, contact the manufacturer or

have a qualified person determine the ventilation requirements.

NOTICE: If you are replacing your old water heater with one that has a higher BTU/h rang, the amount of

venlaon required may be greater.

Gas Burning Appliance BTU/h Rang

Gas Water Heater 140,000

Furnace 75,000

Dryer 20,000

Total 235,000

Example:

Gas Burning Appliance BTU/h Rang

Gas Water Heater

Total

Your

appliances:

Does your installation space have sufficient combustion air?

Venlaon with outside air is recommended for all installaons. Even if the water heater is installed in a

large, open room inside the house, outdoor air is usually needed because modern homes are very ghtly

sealed and oen do not supply enough air to the water heater. However, when installed in a large indoor

space, it may be possible to provide enough air without outside venlaon. If you are unsure if your instal-

laon locaon has enough venlaon, contact your local gas ulity company or code ocials for a safety

inspecon or direct vent.

The following instrucons will help determine if it may be possible to install the water heater without outside

venlaon.

Check for Chemicals:

Installaons where corrosive chemicals may be present require the water heater to be direct vented. Air for

combuson and venlaon must be clean and free of corrosive or acid-forming chemicals such as sulfur, uo-

rine, and chlorine. Venlaon with outside air will reduce these chemicals, but it may not completely eliminate

them. Failure due to corrosive chemicals is not covered by the warranty. Examples of locaons that require

outside air due to chemicals include:

• Beauty salons

• Photo processing labs

• Indoor pools

• Laundry, hobby, or cra rooms

• Chemical storage areas

Products such as aerosol sprays, detergents, bleaches, cleaning solvents, gasoline, air fresheners, paint and

varnish removers, and refrigerants should not be stored or used near the water heater.

16 Page

Calculate the air volume of the room

Air requirements depend on the size of the room.

Room Volume (.

) = Floor Area (.

) X Ceiling Height (.)

If there are large objects in the room (e.g., refrigerator, furnace, car), subtract their volume from the vol-

ume of the room to get a beer esmate of the air available.

Air Volume = Room Volume - Object Volume

NOTE: Adjoining rooms with permanently opened doorways can be counted as part of the calculaon.

Calculate required air volume

A water heater installed in an unconned ac, garage, or space requires that the space be at least 50 cubic

feet per 1,000 BTU/h of the total input for all gas burning appliances in the same area.

Required Air Volume (

) =Total Appliance Energy Rang (btu/h) X 50 

/ 1000 (btu/h)

Example:

(235,000 / 1000) x 50 = 11,750

If the air volume of the room is less than the required air volume, you must direct vent the water heater

or provide permanent outside air openings that draw in sucient air. Go to “Install with outside venla-

on” if you want to provide combuson air with outside venlaon.

If the air volume of the room is greater than the required air volume, it may be possible to install the

water heater without outside venlaon. However, be sure to consider the eects of exhaust fans.

Exhaust fans can aect the amount of combuson air that is available in your home. Appliances such

as furnaces, whole house fans, and clothes dryers draw air out of your home. If they draw air out faster

than it can be replaced, your water heater may not have enough oxygen to re properly. Back-draing

may also result, which is when negave air pressure pulls air backwards through chimneys or appliance

vents. These events can cause unsasfactory water heater performance. The best soluon is to direct

vent the water heater or install an adequate number of make-up air vents. (See “Install with outside ven-

laon.) For more informaon, consult a qualied technician or your local gas ulity.

Install with outside ventilation

Venlaon with outside air is recommended, and, for most installaons, is needed. There may be exisng

venlaon that is adequate, or you may need to add more venlaon.

Supplying outside air to the water heater typically requires two openings. One opening must be within 12

inches from the oor and the second opening must be within 12 inches from the ceiling. Although a single

opening is not preferred, you may use a single opening to outside air if the minimum free area is sized accord-

ing to Table 1. Two openings must be used when venlang with air from another room.

The outside air can be taken from a crawl space or ac open to the outdoors and adequately venlated.

You may use vercal or horizontal ducts.

Determine type of ventilation

There are several types of venlaon that can be used :

1. Direct to outdoors

2. Vercal ducts

3. Horizontal ducts

4. Single opening (not recommended; must be at least 100 square inches. Not appropriate for conned

spaces smaller than 50 cubic feet per 1,000 BTU/h or when geng air from another room.)

5. From a larger room inside the house (not recommended – refer to "Calculate the air volume of the room"

above to determine if the combined volume of the rooms may be adequate).

Determine minimum free area required for each vent opening

The size of the vent openings depends on the total BTU/h rang of all appliances in the space (use your calculaon

from “Before beginning”) and the type of vent used. Table 1 provides the minimum free area for each vent opening

depending on the type of venlaon.

17 Page

Calculate minimum size of vent openings and ducts

The vent cross-seconal area needed to provide the free area depends on the covering on the vent openings. Typical

vents use louvers or grilles to protect the opening. The louver or grill itself blocks some of the free area, so the open-

ing may need to be larger to meet the minimum free area requirements.

Use the following formula to calculate the required cross-seconal area:

Cross-seconal area = minimum free area required ÷ percent free area of covering (in decimals – e.g., 60% = 0.6)

For example, an installaon area that requires openings with 100 square inches of free area would need

134 square inch openings if using metal louvers rated at 75% free area (100 sq. in. ÷ 0.75 = 134 sq. in.).

If you do not know the % free area for your louver or grill, use the following values:

• For wood louvers or grilles: 25%

• For metal louvers or grilles: 75%

Follow these rules to ensure that vents and ducts provide adequate air ow:

• Each vent opening must be no smaller than 100 square inches .

• Ducts must have the same cross-seconal area as free area of the opening.

• Rectangular ducts must have a minimum dimension of no less than three inches .

• All screens must have mesh ¼” or larger.

• Moveable louvers must be locked open or interconnected with the equipment so that they open automa-

cally during operaon.

• Keep louvers and grills clean and free of debris or other obstrucons.

Check that air source is clean and free of chemicals

Air for combuson and venlaon must be clean and free of corrosive or ammable chemicals. A failure due to cor-

rosive chemicals in the air is not covered by the warranty. Combuson air must be free of acid-forming chemicals such

as sulfur, uorine, and chlorine. Be sure that air at the vent inlets is free of such chemicals.

See graphics on next page.

Table 1

Minimum Free Area of Permanent Openings for Venlaon and Combuson Air Supply – Air from outdoor or

indoor spaces.

Based on the total BTU/h input rang for all gas burning appliances within a conned space.

Opening Source Minimum Free Area

Direct to outdoors* 1 sq. in. per 4,000 BTU/hr (see Figure 1, 2)

Vercal ducts 1 sq. in. per 4,000 BTU/hr (see Figure 3)

Horizontal ducts 1 sq. in. per 2,000 BTU/hr (see Figure 4)

Single Opening 1 sq. in. per 3,000 BTU/hr (see Figure 5)

Two permanent openings

to another room**

1 sq. in. per 1,000 Btu/hr (see Figure 6)

Opening: 100 in.

MIN.

Minimum dimension of air openings:

no less than 3 in.

*These openings connect directly with the outdoors through a venlated ac, a venlated crawl space, or through

an outside wall.

** For direcon on combining spaces in dierent stories within the structure, refer to the current edion of the

Naonal Fuel Gas Code ANSI Z223.1/NFPA 54.

18 Page

Combuson Air Supply Opons

Gable vent

to outdoors

Install above

insulaon

Outlet air to

ac 1 in

per

4,000 btu/h

Inlet air from

the crawl space

Open foundaon vent

Conﬁned

Space

Alternate

Air Inlet

1 in

per

4,000 btu/h

Figure 1 - Direct to outdoors openings

Figure 3 - Vercal duct openings

Outlet air to

ac 1 in

per

4,000 btu/h

Inlet air duct

1 in

per

4,000 btu/h

Conﬁned

Space

12” maximum

Gable vent

to outdoors

Install above

insulaon

Figure 5 - SIngle opening

Conﬁned

Space

1 in

per

3,000 btu/h

Alternave

Opening

Locaon

Figure 6 - Two permanent openings

Two permanent

Openings

1 in

per

1,000 btu/h

12” maximum

Conﬁned

Space

Figure 4 - Horizontal duct openings

1 in

per

2,000 btu/h

Conﬁned

Space

Outlet

Inlet

Outdoor

Air Ducts

1 in

per

2,000 btu/h

Figure 2 - Direct to outdoors openings

Two permanent openings

Two permanent

Openings

1 in

per

4,000 btu/h

12” maximum

Conﬁned

Space

19 Page

-Vent length and No. of Elbows-

This is a Category III appliance and must be vented accordingly. The vent system must be sealed airtight.

All seams and joints without gaskets must be sealed with high heat resistant silicone sealant or UL listed

aluminum adhesive tape having a minimum temperature rating of 350 °F (177 °C). For best results, a vent

system should be as short and straight as possible.

• This water heater is a Category III appliance and must be vented accordingly with any 4 in. (102

mm) vent approved for use with Category III or Special BH type gas vent.

• Follow the vent pipe manufacturer’s instructions when installing the vent pipe.

• Do not common vent this appliance with any other vented appliance. (Do not terminate vent

into a chimney. If the vent must go through the chimney, the vent must run all the way through

the chimney with Category III approved or Special BH vent pipe.)

• When the horizontal vent run exceeds 5 ft. (1.5 m), support the vent run at 3 ft. (0.9 m) intervals

with overhead hangers.

• The maximum length of exhaust vent piping must not exceed 60 ft. (18.3 m).* Deduct 5 ft.

(1.5 m) for each 90° elbow used in the venting system. Do not use more than 6 elbows. A 45°

elbow is equivalent to 2.5 ft. of vent length.

*If vent termination kit 9008900005 is used in the installation, the maximun length of exhaust vent

pipe must not exceed 55 ft. (16.8 m) , and the vent run must not exceed 5 elbows. Vent termination kit

9008900005 also has specific DIP switch settings. Refer to p. 22.

Vent type Diameter Max. No. of Elbows Max. Vertical and Horizontal (Total) Vent Length

Intake** 3 in. (76 mm) 6** 60 ft. (18.3 m )*

Exhaust 4 in. (102 mm) 5 55 ft. (16.8 m )*

*For each 90° elbow added, deduct 5 ft. (1.5m) from max. vent length.

**For Intake vent, refer to the above table of the installation of 6 elbows and 60 ft.

Vent type Diameter Max. No. of Elbows Max. Vertical and Horizontal (Total) Vent Length

Intake 3 in. (76 mm) 6 60 ft. (18.3 m )*

Exhaust 4 in. (102 mm) 6 60 ft. (18.3 m )*

*For each 90° elbow added, deduct 5 ft. (1.5m) from max. vent length.

No. of Elbows

Max. Vertical or Horizontal

Vent Length

No. of Elbows

Max. Vertical or Horizontal

Vent Length

0 60 ft. (18.3m) 4 40 ft. (12.2 m)

1 55 ft. (16.8 m) 5 35 ft. (10.7 m)

2 50 ft. (15.2 m) 6 30 ft. (9.1 m)

3 45 ft. (13.7 m)

Excludes elbow termination, rain caps, or the 4 in. (102 mm) Concentric termination.

No. of Elbows

Max. Vertical or Horizontal

Vent Length

No. of Elbows

Max. Vertical or Horizontal

Vent Length

0 55 ft. (16.8 m) 3 40 ft. (12.2 m)

1 50 ft. (15.2 m) 4 35 ft. (10.7 m)

2 45 ft. (13.7 m) 5 30 ft. (9.1 m)

Excludes sidewall termination.

Installaon

Installaon Manual

Standard Vent Terminations (See the next table for vent termination 9008900005.)

Installation with vent termination kit 9008900005

20 Page

-DIP Switch Settings for Vent Length-

Single Pipe with Room-Air Intake

Horizontal Installaon

Wall

Hanger

Sidewall vent

terminaon

Vertical

condensation

drain**

Backflow

preventer*

*Backflow preventer (Recommended for freezing weather conditions: 36 °F (2 °C) and below).

**Vertical condensation drain must be installed in accordance with local codes. It is required to be installed in the vent-

ing system when there is more than 5 ft. (1.5 m) of equivalent vent length, not including the sidewall termination. 90° elbow

is equivalent to 5 ft. (1.5 m) of vent length.

Vercal Installaon

Roof

ashing

Roof

Fire stop

Hanger

Vertical

condensation

drain**

Backflow

preventer*

Rain cap

• Improper venting of this appliance can result in excessive levels of carbon

monoxide which can result in severe personal injury or death.

• Improper installation can cause nausea or asphyxiation, severe injury

or death from carbon monoxide and flue gases poisoning. Improper

installation will void product warranty.

• Specific DIP switch settings are required depending on the length of your

vent run and the type of vent installation. Refer to the following sections

for details:

• Single Pipe with Room Air (page 20)

• Two-pipe Direct Vent (page 21)

• Vent kit of 9008900005 (page 22)

• Outdoor Installation (page 22)

DANGER

110U Indoor (AT-KJr3U-IN)

310U Indoor (AT-K5U-IN)

510U Indoor (AT-D3U-IN)

(Upper bank of DIP switches)

Vent length

No. 6 : O N

No. 7 : OFF

No. 8 : OFF

No. 3 : O N

No. 4 : OFF

No. 5 : OFF

0 to 60 ft.

(0 to 18.3 m)

OFF

1 2 3 4 5 6 7 8 9 10

OFF

1 2 3 4 5 6 7 8

DIP switch settings for single pipe with room-air intake

21 Page

Installaon

Installaon Manual

Two-Pipe, Direct-Vent Installaon Examples

Vertical

condensation

drain**

Horizontal Installaon

Wall

Hanger

Sidewall vent

terminaon

Backflow

preventer*

Fire stop

Vercal Installaon

Vertical

condensation drain**

Backflow

preventer*

Rain cap

Roof ashing

Hanger

Wall

Direct-vent

concentric

terminaon

Horizontal Installaon with

direct-vent concentric terminaon

(Refer to p.10)

110U Indoor (AT-KJr3U-IN)

310U Indoor (AT-K5U-IN)

510U Indoor (AT-D3U-IN)

(Upper bank of DIP switches)

Vent length

No. 6 : O N

No. 7 : OFF

No. 8 : OFF

No. 3 : O N

No. 4 : OFF

No. 5 : OFF

0 to 20 ft.

(0 to 6.1 m)

No. 6 : OFF

No. 7 : OFF

No. 8 : OFF

No. 3 : OFF

No. 4 : OFF

No. 5 : OFF

21 to 40 ft.

(DEFAULT)

(6.2 to 12.2 m)

No. 6 : O N

No. 7 : O N

No. 8 : OFF

No. 3 : ON

No. 4 : ON

No. 5 : OFF

41 to 60 ft.

(12.3 to 18.3 m)

OFF

1 2 3 4 5 6 7 8 9 10

OFF

1 2 3 4 5 6 7 8

OFF

1 2 3 4 5 6 7 8 9 10

OFF

1 2 3 4 5 6 7 8

OFF

1 2 3 4 5 6 7 8 9 10

OFF

1 2 3 4 5 6 7 8

DIP switch settings for direct vent installation

*Backflow preventer (Recommended for freezing weather

conditions: 36 °F (2 °C) and below).

**Vertical condensation drain must be installed in accordance with

local codes. It is required to be installed in the venting system when there

is more than 5 ft. (1.5 m) of equivalent vent length, not including the sidewall

termination. 90° elbow is equivalent to 5 ft. (1.5 m) of vent length.

Direct-vent sidewall Installaon

(Refer to p.23)

1 ft. (305 mm)

min.

0.4 ft.

(130 mm)

min.

0.4 ft.

(130 mm)

min.

Exhaust

Intake

Exhaust

Intake

22 Page

Two-Pipe, Direct-vent

sidewall Installaon

Single Pipe

with Room-Air Intake

Installaon

Installaon Manual

Horizontal Installaon with the 9008900005 vent kit

Covering wall thicknesses Part#

Termination 9008899005

Wall Thimble 9008898005

Termination + Thimble 9008900005

110U Indoor (AT-KJr3U-IN)

310U Indoor (AT-K5U-IN)

510U Indoor (AT-D3U-IN)

(Upper bank of DIP switches)

Vent length

No. 6 : O N

No. 7 : O N

No. 8 : OFF

No. 3 : ON

No. 4 : ON

No. 5 : OFF

0 to 55 ft.

(0 to 16.8 m)

OFF

1 2 3 4 5 6 7 8 9 10

OFF

1 2 3 4 5 6 7 8

For the Direct vent kit of 9008900005, set the following DIP switch settings.

Outdoor Installaon DIP switch sengs

110U Outdoor (AT-KJr3U-OS)

310U Outdoor (AT-K5U-OS)

510U Outdoor (AT-D3U-OS)

(Upper bank of DIP switches)

No. 6 : OFF

No. 7 : O N

No. 8 : OFF

No. 3 : OFF

No. 4 : O N

No. 5 : OFF

OFF

1 2 3 4 5 6 7 8 9 10

OFF

1 2 3 4 5 6 7 8

Outdoor installation

9008900005 (Termination + Thimble)

9008898005

(Wall Thimble)

3 - 6"

9008899005

(Termination)

2 - 5"

3 - 7"

*Backflow preventer (Recommended for freezing weather conditions: 36 °F (2 °C) and below.)

**Vertical condensation drain must be installed in accordance with local codes. It is required to be installed in the vent-

ing system when there is more than 5 ft. (1.5 m) of equivalent vent length, not including the sidewall termination. 90° elbow is

equivalent to 5 ft. (1.5 m) of vent length.

Vertical

condensation

drain**

Vertical

condensation

drain**

Backflow

preventer*

Backflow

preventer*

23 Page

Installaon

Installaon Manual

-Clearances for rooftop terminations-

• Exhaust terminations must be at least 1 ft. (305 mm) away from any obstructions.

• In lieu of using roof caps, a 90 degree elbow and 45 degree elbow can be used for the exhaust, and

two 90 degree elbows can be used for the air intake.

2 ft (610 mm) min.

1 ft

(305 mm) min.

1 ft

(305 mm) min.

Intake air

Exhaust

gas

Anticipated

snow level

3 ft (914 mm) min.

1 ft

(305 mm) min.

1 ft

(305 mm) min.

Intake air

Exhaust

gas

Anticipated

snow level

-Clearances for sidewall terminations-

1 ft. (305 mm) min.

Exhaust

Intake

0.4 ft.

(130 mm)

min.

Exhaust

Intake

0.4 ft.

(130 mm)

min.

1 ft. (305 mm)

min.

0.4 ft.

(130 mm)

min.

0.4 ft.

(130 mm)

min.

Exhaust

Intake

Exhaust

Intake

For direct-vent sidewall terminations that use two separate penetrations for the intake and exhaust,

comply with the minimum clearances shown in the diagrams below.

24 Page

For multiple sidewall exhaust terminations (e.g. multi-

unit systems), an exhaust termination must be at least 1

ft. (305mm) away from another exhaust termination. An

exhaust termination must also be at least 2 ft. (610 mm)

away from an inside corner. If the adjacent wall is less than

2 ft. (610 mm) of length, the minimum required distance

away from the inside corner will be equal to the length of

that adjacent wall.

For multiple-unit, direct-vent sidewall terminations that

combine the intake and exhaust into a single penetration,

space each direct-vent termination at least 1 ft. (305 mm)

away from each other, no matter the orientation. A direct-

vent termination must also be at least 2 ft. (610 mm) away

from an inside corner. If the adjacent wall is less than 2 ft.

(610 mm) of length, the minimum required distance away

from the inside corner will be equal to the length of that

adjacent wall.

For direct-vent sidewall

terminations that use two

separate penetrations for

the intake and exhaust,

distance the intake and

exhaust terminations at

least 3 ft. (915 mm) away

from each other, no

matter the orientation

unless they follow case 1

and 2 on p. 23.

For multiple-unit rooftop terminations (whether for standard or direct-vent installations) space all

exhaust and intake terminations in accordance with local codes. An exhaust termination must be spaced

from a wall or surface in accordance with local codes as well. In the absence of such a code, an exhaust

termination must be a horizontal distance of at least 2 ft. (610 mm) away from a wall or surface.

Exhaust and/or

direct-vent sidewall

terminations should

be at least 2 ft. (610

mm) away from an

opposite surface/

wall. Do not place

the termination

directly in front of

an opening into a

building.

Please follow all local and national codes in regards to proper termination

clearances. In the absence of such codes, the above clearances can be used as

guidelines. Local codes supersede these guidelines.

CAUTION

Ancipated Snow level

3.

(915 mm)

min.

3.

(915 mm)

min.

1.

(305 mm)

min.

Air supply

inlet

Air supply

inlet

Air supply

inlet

Exhaust

terminaon

Installaon

Installaon Manual

Ancipated Snow level

Exhaust

Terminaon

2.

(610 mm)

min.

1.

(305 mm)

min.

1.

(305 mm)

min.

Inside

corner

Inside

corner

Ancipated Snow level

2.

(610 mm)

min.

1.

(305 mm)

min.

1.

(305 mm)

min.

Combined

intake and

exhaust

terminaon

Exhaust

termination

2 ft. (610 mm)

min

A & B- In accordance with local codes

Ancipated

snow level

Roof

Air intake

Exhaust terminaon

Ancipated

snow level

Air intake

Exhaust

terminaon

2.

(610 mm) min

-Clearances for mulple sidewall terminaons-

-Clearances for mulple rooop terminaons-

25 Page

-Vent terminaon clearances-

Canada U.S.A

Direct-vent and other

than Direct-vent

Direct-

vent

Other than

Direct-vent

Clearance above grade, veranda, porch, deck, or bal-

cony

1 foot

(30 cm)

1 foot

(30 cm)

1 foot

(30 cm)

Clearance to window or door that may be opened

3 feet

(91 cm)

1 foot

(30 cm)

4 feet (122 cm) from

below or side opening. 1

foot (30 cm) from above

opening.

Clearance to permanently closed window

* * *

Vertical clearance to ventilated soffit located above

the vent terminator within a horizontal distance of 2

feet (61cm) from the center line of the terminator

* * *

Clearance to unventilated soffit

* * *

Clearance to outside corner

* * *

Clearance to inside corner

2 feet

(61 cm)

2 feet

(61 cm)

Clearance to each side of center line extended above

meter/regulator assembly

3 feet

(91 cm)

* *

Clearance to service regulator vent outlet

3 feet

(91 cm)

* *

Clearance to non-mechanical air supply inlet to build-

ing or the combustion air inlet to any other applica-

tion

3 feet

(91 cm)

1 foot

(30 cm)

4 feet (122 cm)from

below or side opening. 1

foot (30 cm) from above

opening.

Clearance to mechanical air supply inlet.

6 feet

(1.83 m)

3 feet

(91 cm)

3 feet

(91 cm)

Clearance above paved sidewalk or paved driveway

located on public property

7 feet

(2.13 m)

7 feet

(2.13 m)

Clearance under veranda, porch deck, or balcony

1 foot

(30 cm)

* *

*For clearances not specified in ANSI Z223.1 / NFPA 54 (USA) or B149.1 (Canada), please use clearances in accordance

with local installation codes and the requirements of the gas supplier.

INSIDE CORNER DETAIL

Gas meter / regulator

Vent terminal

Air supply inlet

Area where is not permitted

OPERABLE

FIXED

CLOSED

OPERABLE

FIXED

CLOSED

Installaon

Installaon Manual

26 Page

GAS SUPPLY AND GAS PIPE SIZING

-General-

• Minimum and maximum inlet gas pressures:

• Inlet gas pressures that fall outside the range of values listed above may adversely affect the

performance of the water heater. These pressures are measured when the water heater is in full

operation and when it is in stanby.

• Inlet gas pressure must not exceed the above maximum values; gas pressure above the specified range

will cause dangerous operating conditions and damage to the unit.

• Until testing of the main gas line supply pressure is completed, ensure the gas line to the water heater

is disconnected to avoid any damage to the water heater.

• If the gas supply pressure to the heater is greater than the specified maximum, a field-supplied

regulator is required. The regulator must lower the gas pressure within the approved range.

• Install the gas regulator according to the manufacturer's instructions.

• The regulator must be sized for the water heater input and provide the specified pressures that

are listed on the rating plate.

• In the absence of minimum install distance, it is recommended that the gas regulator be installed

no closer than 3 ft. (1 m) from the water heater's inlet gas connection.

-Gas connecons-

1. Install a full port, manual gas shutoff valve between the water heater and the gas supply line.

2. When the gas connections are completed, it is necessary to perform a gas leak test either by applying

soapy water to all gas fittings and observing for bubbles or by using a gas leak detection device.

• The water heater and its individual shutoff valve must be disconnected from the gas supply

piping system during any pressure testing of that system at test pressures in excess of 1/2 psi

(3.5 kPa).

• The water heater must be isolated from the gas supply piping system by closing its individual

manual shutoff valve during any pressure testing of the gas supply piping system at test

pressures equal to or less than 1/2 psi (3.5 kPa).

3. Always purge the gas line of any inert gas, debris, and/or water before connecting to the gas inlet.

Size the gas pipe to supply the necessary volume of gas for the water heater. Refer

to and follow the requirements listed in the current edition of ANSI Z223.1/NFPA

54 (USA), B149.1 (Canada), or local codes. Otherwise, flow capabilities and output

temperatures will be limited.

NOTICE

Gas type Inlet gas pressure

Natural Gas Min. 4.0” W.C. (1.00 kPa) – Max. 10.5” W.C. (2.61 kPa)

Propane Min. 8.0” W.C. (1.99 kPa) – Max. 14.0” W.C. (3.48 kPa)

• Do not use this water heater with any gas other than the one listed on the

rating plate unless the water heater has been properly converted.

• Ensure that any and all gas regulators used are operating properly and

providing gas pressures within the specified range shown below. Excess gas

inlet pressure may cause serious accidents.

• If your water heater needs a gas conversion, refer to the instructions supplied

with the water heater and included with the conversion components.

Installaon

Installaon Manual

WARNING

27 Page

Based on Energy

Content of 1,000

BTU/Cubic ft:

Divide each

appliance's BTU/h

requirement by

1,000 BTU/ft

to get

the appliance's ft

requirement.

Take into account

the distance the

appliance is from

the gas meter, then

look in the above

gas chart to properly

size the line.

For sections of the

gas line supplying gas to more than one appliance (Ex: Point A to Point B), add up the cubic ft. per hour requirements

of the appliances that are being supplied by that section, and size to the farthest appliance.

For Example: The section from A to B supplies gas to the furnace, range and dryer. Adding up the BTU/h requirements

and dividing by 1,000 yields a cubic ft. per hour requirement of 220 cubic ft. of gas per hour. The farthest appliance

is the range, which is 50 ft. (15.2 m) away from the meter. According to the chart above, the 50-ft. (15.2 m) column

shows that Section A to B must be 1" in order to supply 220 cubic ft per hour.

Water

heater

199,000 BTU/h

Dryer

35,000 BTU/h

Gas meter

Furnace

120,000 BTU/h

Range

65,000 BTU/h

10' (3.1 m) Length

1/2" Pipe size

15' (4.6 m) Length

1/2" Pipe size

15' (4.6 m) Length

1" Pipe size

10' (3.1 m) Length

3/4" Pipe size

10' (3.1 m) Length

1" Pipe size

5' (1.5 m) Length

1-1/4" Pipe size

10' (3.1 m) Length

3/4" Pipe size

5' (1.5 m) Length

1-1/4" Pipe size

Gas sizing example

(Natural Gas)

Installaon

Installaon Manual

Pipe Size Length: ft. (m)

Diameter:

in.

10'

(3.0)

20'

(6.1)

30'

(9.1)

40'

(12.2)

50'

(15.2)

60'

(18.3)

70'

(21.3)

80'

(24.4)

90'

(27.4)

100'

(30.5)

125'

(38.1)

150'

(45.7)

200'

(61.0)

1/2"

172 118 95 81 72 65 60 56 52 50 44 40 34

3/4"

360 247 199 170 151 137 126 117 110 104 92 83 71

1" 678 466 374 320 284 257 237 220 207 195 173 157 134

1/4"

1,309 957 768 657 583 528 486 452 424 400 355 322 275

1/2"

2,090 1,430 1,150 985 873 791 728 677 635 600 532 482 412

2" 4,020 2,760 2,220 1,900 1,680 1,520 1,400 1,300 1,220 1,160 1,020 928 794

Unit: Cubic feet per hour

-Natural Gas Supply Piping-

Maximum delivery Capacity of Cubic Feet of Gas per Hour of IPS Pipe carrying Natural Gas with 0.60 Specific Gravity

Based on Pressure Drop of 0.5" W.C.

Based on Energy Content of 1,000 BTU/Cubic ft.: The water heater requires 140 Cubic ft./hr for the 110U,

190 Cubic ft./hr for 310U, and 199 Cubic ft./hr for the 510U model.

The following tables are from NFPA 54

Unit: kBTU per hour

Pipe Size

Length: ft. (m)

Diameter

10'

(3.0)

20'

(6.1)

30'

(9.1)

40'

(12.2)

50'

(15.2)

60'

(18.3)

70'

(21.3)

80'

(24.4)

90'

(27.4)

100'

(30.5)

125'

(38.1)

150'

(45.7)

200'

(61.0)

1/2"

268 184 148 126 112 101 93 87 82 77 68 62 53

3/4"

567 393 315 267 237 217 196 185 173 162 146 132 112

1,071 732 590 504 448 409 378 346 322 307 275 252 213

1/4"

2,205 1,496 1,212 1,039 913 834 771 724 677 630 567 511 440

1/2"

3,307 2,299 1,858 1,559 1,417 1,275 1,181 1,086 1,023 976 866 787 675

6,221 4,331 3,465 2,992 2,646 2,394 2,205 2,047 1,921 1,811 1,606 1,496 1,260

-Propane (LP) Supply Piping-

Maximum Capacity of Propane (LP) Based on 11" W.C. supply pressure at a 0.5" W.C. pressure drop

28 Page

Pressure port

Cold

inlet

Hot

outlet

Gas

inlet

As Close as

Possible

Pressure relief valve

Installaon

Installaon Manual

-Measuring inlet gas pressure-

The water heater cannot perform properly without sufficient inlet gas pressure. Below are instructions

on how to check the inlet gas pressure. THIS IS ONLY TO BE DONE BY A LICENSED PROFESSIONAL.

1. Shut off the manual gas valve on the gas supply line.

2. Remove the screw for the pressure port located on the gas inlet of

the water heater shown in the diagram on the right.

3. Connect the manometer to the pressure port.

4. Re-open the manual gas valve. Verify that there are no gas leaks.

5. With all gas burning equipment off, take a reading of the static gas

pressure.

6. Measure gas supply pressure at maximum heater operation: Open

up water faucets to create maximum flow. Press and hold the

MAX button on the computer board. Take a reading of the supply

dynamic gas pressure with all gas burning equipment running at

maximum rate.

7. The static and dynamic pressures should be within the ranges

specified on the heater's rating plate and the table on p. 26.

8. The difference of static to dynamic pressure should not exceed

1.5" W.C. Pressure drops that exceed 1.5" W.C. can indicate

restricted gas flow, undersized gas lines, and/or undersized supply regulators.

1. Turn off all electric power to the water heater if service is to be performed.

2. Turn the manual gas valve located on the outside of the unit to the OFF position.

WARNING

• Do not use this water heater if any part has been submersed under water. Do not attempt

to repair the unit. It must be replaced. Failure to follow these instructions could lead to

property damage, personal injury, or loss of life.

WARNING

• Do not reverse the hot outlet and cold inlet connections to the water heater.

This will not activate the water heater properly.

NOTICE

4. Before installing the water heater, flush the

water line to remove all debris, and after

installation is complete, purge the air from

the line. Failure to do so may cause damage

to the water heater.

5. There is a wire mesh filter within the cold

inlet to trap debris from entering your heater.

This will need to be cleaned periodically to

maintain optimum flow. (Refer to p. 46.)

All pipes, pipe fittings, valves and other components, including soldering materials, must be suitable for

potable water systems.

1. A manual shutoff valve must be installed on the cold water inlet to the water heater between the

main water supply line and the water heater.

2. In addition, a manual shutoff valve is also recommended on the hot water outlet of the unit.

Isolation valves are recommended as shown in the picture at right.

3. If the water heater is installed within, or subjected to, a closed

loop water system, a thermal expansion tank must be installed to

handle thermal expansion.

WATER CONNECTIONS

29 Page

-Pressure relief valve-

The water heater has a high-temperature shutoff switch built in as a standard safety feature (called a

Hi-Limit switch). Therefore, a “pressure only” relief valve is required.

• This unit does not come with an approved pressure relief valve.

• An approved pressure relief valve must be installed on the hot water outlet.

• The pressure relief valve must conform to the current edition of ANSI Z21.22 or CAN 1-4.4 and instal-

lation must follow local codes.

• The discharge capacity must be at least 140,000 BTU/h for the 110U model, 190,000 BTU/h for the

310U model, and 199,000 BTU/h for the 510U model.

• The pressure relief valve must be rated for a maximum of 150 psi (1 MPa).

• The discharge piping for the pressure relief valve must be directed so that the hot water cannot splash

on anyone or on nearby equipment.

• Attach the discharge tube to the pressure relief valve and run the end of the tube to within 6 in.

(152 mm) from the floor. This discharge tube must allow free and complete drainage without any

restrictions.

• If the pressure relief valve installed on the water heater discharges periodically, this may be due to a

defective thermal expansion tank or defective pressure relief valve.

• The pressure relief valve must be manually operated periodically to check for correct operation.

WARNING! Hot water will be released. The contact of discharge may cause property damage and/

or bodily harm. Before operating the pressure relief valve manually, check that it will discharge in

a safe place. If water does not flow freely from the end of the discharge pipe, turn the gas supply

OFF and call a qualified person to determine the cause.

• No valve shall be placed between the relief valve and the water heater.

ELECTRICAL CONNECTIONS

All indoor models come with a power plug instead of a junction box. The following procedure is for

outdoor models only.

1. The water heater must be electrically grounded. Do not attach the ground wire to either the gas or

the water piping.

2. The water heater requires 120 VAC, 60 Hz electrical power supply that is properly grounded.

• A proper disconnect (i.e. on/off switch, power plug, etc.) controlling the main power to the water

heater must be provided for service reasons. (Must comply with local codes.)

• Connect the power supply to the water heater exactly as shown in the wiring diagram.

3. A green screw is provided in the junction box to ground the connection.

4. Can be hardwired or wired to a plug-in.

5. The use of a surge protector is recommended in order to protect the unit from power surges.

• Ensure that circuit power is turned OFF before you complete the following steps.

• Follow the electrical code requirements of the local authority having jurisdiction.

In the absence of such requirements, follow the current edition of the National

Electrical Code ANSI/NFPA 70 in the U.S. or the current edition of CSA C22.1 Canadian

Electrical Code Part 1 in Canada

• When servicing or replacing parts within the water heater, label all wires prior to dis-

connection to facilitate an easy and error-free reconnection. Wiring errors can cause

improper and dangerous operation. Verify proper operation after servicing.

• Failure to follow these instructions can result in fire, electrical shock, or death.

WARNING

Outdoor models only

Boom view of water heater

View of electrical

connecons of water heater

Ground

wire with

terminal

Connect

power supply

120VAC, 60Hz

Green screw

Indoor models only

Installaon

Installaon Manual

30 Page

TEMPERATURE REMOTE CONTROLLER

-Included Accessories-Outdoor models only-

It is also an optional accessory as a second remote for the indoor models. The optional remote con-

troller doesn't come with the remote cable. Refer to p. 9.

Mounting and wiring the remote controller

1. Take off the “Back plate” from the remote controller with a flat head screwdriver. (Fig. A and B)

2. Attach the “Back plate” on the wall with the two provided screws. (Fig. B)

Fig. B

Back plate

3-1/4 inches

Attach the screws

Cut out the partition with pliers

Main body

Fig. A

Main body

Twist

Press and twist flat head

screwdriver against the cutout.

Check that these items below are included with the remote controller.

Temperature

remote controller*

Screws Manual Remote controller cable

Qty: 1 Qty: 2 Qty: 1

Qty: 1

Installaon

Installaon Manual

*9009069005 (TM-RE42)

This remote controller is NOT waterproof.

The water heater can only have one remote controller at a time.

Do not install in high temperature environments, high humidity conditions out-

doors, in direct sunlight, or within the reach of children.

Make sure the remote controller does not come into contact with water or oil.

• Do not place the remote control wiring close to other wires from other

products.

• Do not extend the remote control wiring more than 400 ft. (122 m.)

CAUTION

-Installaon-

31 Page

Installaon

Installaon Manual

Crimp the "Fork terminals" to the cable. (Fig. C)

Tighten the two "Fork terminals" beneath the two

"Remote controller terminal" screws on the back of

the main body. (Fig. D-1)

Cut out the inlet for the remote controller cable

from the bottom of the main body. (Fig. D-2)

Place the "Main body" back on the "Back plate",

with the "Remote controller cable" running out of

the bottom inlet.

Remote controller

terminals

Fig. D-1

Two fork terminals

Remote controller cable

Inlet for the remote

controller cable

Cut out

Fig. D-2

Remote controller cable

1-3/8 Inch

(35 mm)

Fig. C

1-5/8 Inch

(41 mm)

Fork

Terminals

Connecting the remote controller to the water heater

1. Disconnect power supply from the water heater.

2. Take off the water heater’s front cover.

3. Locate the two terminals for the remote controller in the water heater. (Refer to the Fig. E-1 and E-2.)

4. Put the remote controller cable through the hole at the bottom of the water heater's casing from

outside.

5. Properly connect the two terminals attached to the end of the remote control wires to the terminals

for the remote controller on or near the computer board with the screws. (No polarity)

* Do NOT jump or short-circuit the wires, or the computer will be damaged.

6. Replace the water heater's front cover securely.

Wires used for the remote controller connection must be:

• Minimum 20 gauge wire (No polarity)

• Maximum 400 ft. (122 m) long

110U (AT-KJr3U-IN/OS) and 310U (AT-K5U-IN/OS)

9009069005

(TM-RE42)

Front of remote

Connect other end to these terminals

Fig. E-1

9009069005

(TM-RE42)

Front of remote

Connect other end to these terminals

510U (AT-D3U-IN/OS)

Fig. E-2

32 Page

EASY-LINK SYSTEM

Available on the 510U (AT-D3U-IN/OS) model only

The 510U (AT-D3U-IN/OS) model water heaters can be connected with other allowable heaters

(see the table below) with communication cables to work as a multiple-unit manifold system.

• The Easy-Link System allows up to 4 units to manifold together.

• A communication cable (gray color) comes with each 510U (AT-D3U-IN/OS) model.

You can manifold from 2 to 4 units without the need for a multi-unit controller. A 4-unit system

has full automatic modulation between 15,000 BTU/h and 796,000 BTU/h.

-Easy-Link Connecon Procedures-

1. Make sure the power to the heaters is turned off.

2. Verify the DIP switch set temperatures of all units within the system. Every water heater must be set

to the same set temperature. If an optional remote controller (9009069005/TM-RE42) is used, it

should be installed to the “PARENT” unit. (See section B on the naxt page.) The remote will set the

temperature for the entire system.

3. Select one unit to be the “PARENT” unit. The “PARENT” unit should be one of the end units.

4. “PARENT” unit:

Locate the two banks of DIP switches at the bottom left of the computer board of the unit that you

select to be the “PARENT” unit. Change DIP switch No. 1 on the lower bank of DIP switches to the

ON position. See the computer board diagram as shown on the next page. Do not change any DIP

switches on any of the “CHILD” units.

5. Between the “PARENT” and the “CHILD-1” units:

Connect the “PARENT” connector of the “PARENT” unit to the “1” connector of the “CHILD-1” unit

using the supplied linking cable.

6. Between the “CHILD-1” and the “CHILD-2” units:

Connect the “2” connector of the “CHILD-1” unit to the “1” connector of the “CHILD-2” unit.

• The Easy-Link System is limited to up to 4 units. If you connect more than 4

units, only the first 4 units will work as a part of the Easy-Link System. The

other additional units will not work as part of the system.

• Only listed models on the table above can be combined together as an

Easy-Link System. These models cannot be combined together with other

models not listed on the table above.

CAUTION

-General-

Installaon

Installaon Manual

OFF

The dark square indicates the correct DIP switch position.

DIP switch setting on the 510U (AT-D2U-IN/OS) and 510U (AT-D3U-IN/OS)

(Lower bank of DIP switches)

Easy-Link connection

with allowable heaters

T-K3

T-K3-Pro

510 model (AT-D2-IN/OS)

510U model (AT-D2U-IN/OS)*

510U model (AT-D3U-IN/OS)*

200 series

*If the 510U (AT-D2U-IN/OS) models and the 510U (AT-D3U-IN/OS) models are incorporated in an Easy-

Link Sytem with the other models in the table above, change DIP switch No. 6 on the lower bank of all

the 510U (AT-D2U-IN/OS) and 510U (AT-D3U-IN/OS) computer boards to the “ON” position.

Gas In

Hot Out

Cold In

33 Page

7. Between the “CHILD-2” and the “CHILD-3” units:

Connect the “2” connector of the “CHILD-2” unit to the “1” connector of the “CHILD-3” unit.

8. Verify that all cables are connected like the diagram (B).

9. Turn on power to the “PARENT” unit.

Next, turn on “CHILD-1”. When the controller* installed in “CHILD-1” unit displays a number, turn on

“CHILD-2”.

When the controller* installed in the “CHILD-2” unit displays a number, turn on “CHILD-3”.

Make sure the controller* installed in each child unit displays each unit number. (Refer to p. 48.)

The numbering system automatically allocates the unit number to each water heater in the Easy-Link

System, in accordance with the table on the right.

10. Set the water temperature using the controller* installed

in the “PARENT” unit. It will set the temperature for the

Easy-Link System. If a remote controller is installed to the

“PARENT” heater of 510 U Indoor (AT-D3U-IN), it will over-

ride the built-in controller.

*Built-in controller for indoor models, remote controller for outdoor models.

(A) 510U (AT-D3U-IN/OS) model Computer board

To change the DIP switch

settings for the Easy-Link

System, locate the bank of

DIP switches at the bottom

left of the computer board.

Do not adjust the upper

bank of DIP switches.

Easy-Link /

Mul-Unit

connectors

are next to

the computer

board.

Lower bank of DIP switches

Upper bank of DIP switches

(B) Basic diagram of connections between the Easy-Link System units

NOTE: The dark square indicates the correct DIP switch position.

PARENT

Communicaon cable

Lower bank of

DIP switches

OFF

PARENT

OFF

Lower bank of

DIP switches

Lower bank of

DIP switches

Lower bank of

DIP switches

Connectors Connectors Connectors Connectors

PARENT unit

CHILD-1 unit CHILD-3 unit

CHILD-2 unit

Remote controller

Installaon

Installaon Manual

• A remote controller is not required for an Easy-Link System. However, it does

provide for more temperature options and ease of maintenance.

• If a remote controller is used, the temperature on all units in the system will

automatically be set to the same temperature that is set on the remote.

NOTICE

Type of unit Unit # of easy-link

Parent 1

Child 2, 3, or 4

34 Page

Installaon

Installaon Manual

• The parent/child DIP switch, No.1 on the lower bank of DIP switches, should be in the OFF

position.

• This is the connection diagram between 510U (AT-D3U-IN/OS) and multi-unit controller

for 2 to 20 water heaters. Above is an example showing seven water heaters.

• The multi-unit controller automatically allocates the unit number (1-20) to each water

heater that is part of the Multi-Unit System.

• In a Multi-Unit System, connect the “[1]” connector and the “[2]” connector with the

communication cable (refer to p. 9) or 18 gauge wire cables. The total cable length can

be up to 250 ft. (76.2 m) long.

For detailed instructions on the multi-unit controller, refer to the

instructions that are packaged with the multi-unit controller.

9008300005

(TM-MC02)

510U

Cold IN

Hot Out

MULTI-UNIT SYSTEM

Multiple 510U (AT-D3U-IN/OS) models can be combined for a Multi-Unit System, along with the

multi-unit controller (Part 9008300005 (TM-MC02)). Each multi-unit controller can control from 2 to

20 units for commercial or residential applications. For a 20-unit system, the computer can modulate

from 15,000 BTU/h to 3.98 million BTU/h.

An individual cut-off switch is recommended

for each unit in a Multi-Unit System for the

purpose of maintenance.

Multi-Unit System connection diagram

Multi-unit controller and temperature remote controller wiring:

Remote controller

9008300005

(TM-MC02)

Terminals for

water heaters

Remote

controller

terminals

OFF

PARENT

Connectors Connectors Connectors

OFF

Lower bank of

DIP switches

Lower bank of

DIP switches

Lower bank of

DIP switches

Lower bank of

DIP switches

Lower bank of

DIP switches

Lower bank of

DIP switches

Lower bank of

DIP switches

Communicaon cable

Remote controller cable

PARENT

Connectors Connectors

OFF

PARENT

Connectors Connectors

OFF

Example : 510U (AT-D3U-IN/OS) x 7 units

35 Page

APPLICATIONS

SPACE-HEATING APPLICATIONS

RECIRCULATION

*The recirculation pump is to be controlled by:

-Dual-set aquastat (recommended w/timer)

• The aquastat's differential should be a minimum of 10 °F (5 °C).

*The recirculation pump is to provide no less than 2 GPM (7.5 L/min) and no more than 4 GPM (15 L/min) through

each activated unit in the system. Refer to the heaters specification sheet on the manufacturer's website for

pressure drop information.

• This water heater is suitable for combination water (potable) heating and space

heating and not suitable for space heating applications only.

• In order to purge air in water pipes within a closed-loop system, an air vent and

air separator should be installed in the system. Required circulation flow rates are

labeled next to each application diagram. These flow rate requirements must be

followed.

• Toxic chemicals used in boiler treatments such as alcohol, glycerol and glycol groups

must not be introduced into the system.

• The water heater can be used to supply combination potable water and space

heating and shall not be connected to any heating system or component(s)

previously used with non-potable water where any chemicals were added to the

water heating appliances.

• When the system requires water for space heating at temperatures higher than

required for other uses, a means such as a mixing valve shall be installed to temper

the water for those other uses in order to reduce scald hazard potential.

• Water temperature over 125 °F (52 °C) can cause severe burns instantly or death

from scalding.

WARNING

Air vent

Hot water outlet to xtures

Recirculaon

pump

Air

separator

Check valve

Y-Strainer

Cold water inlet

Expansion tank

Gas supply

Ball valves

Unions

Hot water outlet

Cold water inlet

Gas inlet

Pressure

relief valve

This is a concept drawing only.

Applicaons

36 Page

• Priority Control Devices such as a flow switch, an Aquastat or other

electronic controller can be used to prioritize the domestic water system over

the heating system.

• Follow all local codes, or in the absence of local codes, follow the current

edition of the National Standard Code, ANSI Z21.10.3 ・ CSA 4.3.

• This illustration is a concept design only. The reference to the 1/8-inch hole

in the check valve is only required in the State of Massachusetts. There are

a wide variety of variations to the application of controls and equipment

presented. Designers must add all necessary safety and auxiliary equipment

to conform to code requirements and design practice. For more details,

contact the manufacturer or local code authority.

NOTICE

DUAL-PURPOSE HOT WATER HEATING

(Domestic and Space Heating):

Diagrammatic layout of radiant heating and domestic water heater per Massachusetts code.

The recirculation pump is to provide no less than 2 GPM (7.5 L/min) and no more than 4 GPM (15 L/min)

through each activated unit in the system

Installaon

Installaon Manual

Ball

Valve

Isolation

Valve

120 VAC

switch or

outlet

Hot water outlet

Unions

T-handle gas shuto valve

Check valve

Electronically controlled

pump mer. Acvates

every 6 hours for 60

seconds. Wire to

product approved pump

Heang Coil

(used with air-handler)

Cold water supply

3" intake and 4" vent

(Discharge must

comply with local and

state codes.) Cannot

be common vented

with other appliances

An approved temperature and pressure

relief valve. Tie to locaon approved by

local codes and must meet BTU rang of

water heater model used

Check valve will have

1/8-inch hole drilling

in clapper.

Atmospheric

vacuum

breaker

Shuto

valve

Pressure

gauge

Apply correct thermal

expansion tank-size

per applicaon

Shuto valves

Check valves

Cold water inlet

Gas inlet

Water

lter

Drain

plug

Thermostac mixing valve

Hot water

supply and

return to

heang coil

System installed with reverse

acng aquastat to shut o fan.

Suggested but not required by

248 CMR

50’-0” MAXIMUM DISTANCE FROM

WATER HEATER TO FAN COIL AND

BACK (DEVELOPED LENGTH) NOT

INCLUDING COIL IN HEATING UNIT.

NSF-61 product

approved pump

Automac tempering device

must be installed below

the top of the water heater

as per manufacturer’s

recommendaons

Piping loop

between water

heater and fan

coil shall be in

compliance with

248 CMR

Tempered water to

plumbing xtures. Must

meet temperature

requirements of 248 CMR

All water piping should be insulated

in accordance with 780 CMR

(Massachuses energy code)

Water heater

accepted by

the Board for

installation in

Massachusetts.

37 Page

INITIAL OPERATION

Operation

Once the above checks have been completed, please clean the filter

of any debris. Refer to p. 46 for instructions.

Fully open the manual water control valve on the water supply line.

Open a hot water tap to verify that water is flowing to that tap. Then

close the hot water tap.

Fully open the manual gas control valve.

Turn on the 120 VAC, 60 Hz power supply to the water heater.

Now you are ready to enjoy hours of endless hot water.

• Check the GAS and WATER CONNECTIONS for leaks before firing the unit for the first time.

• Open the main gas supply valve to the unit using only your hand to avoid any spark. Never use

tools. If the knob will not turn by hand, do not try to force it; call a qualified service technician.

Forced repair may result in a fire or explosion due to gas leaks.

• Be sure to check for the presence of leaking gas toward the bottom of the unit because some

gases are heavier than air and may settle toward the floor.

• Check the GAS PRESSURE. Refer to p. 26.

• Do not try to light the burner manually. It is equipped with an electronic ignition device which

automatically lights the burner.

• Check for PROPER VENTING and COMBUSTIBLE AIR to the water heater.

• Purge the GAS and WATER LINES to remove any air pockets.

• Do not use this water heater if any part has been submersed under water. Do not attempt to

repair the unit. It must be replaced. Failure to follow these instructions could lead to property

damage, personal injury, or loss of life.

FOR YOUR SAFETY, READ BEFORE OPERATING

Inial operaon

Installaon Manual

IF YOU SMELL GAS:

• Do not try to start the water heater.

• Do not touch any electric switches; do not use any phone in your building.

• Immediately call your gas supplier from a neighbor’s phone. Follow the gas

supplier’s instructions.

• If you cannot reach your gas supplier, call the fire department.

WARNING

38 Page

Owner's Guide

CONGRATULATIONS

Congratulations and thank you for choosing our tankless water heater.

Before use, we recommend that you read through this owner's guide

carefully. Please refer to the back of the manual for details about the

warranty. Keep this manual for future reference.

If you need an additional manual, contact the manufacturer or your

local distributor. When you call, please tell us the product name and

the serial number of your unit written on the rating plate of the water

heater.

Owner's Guide

39 Page

OPERATING SAFETY

Operang Safety

Owner's Guide

WARNING:

If you do not follow these instructions exactly, a re or explosion may result

causing property damage, personal injury or loss of life.

A. This appliance does not have a pilot. It is equipped with an ignition device which automatically

lights the burner. Do not try to light the burner by hand.

B. BEFORE OPERATING smell all around the appliance area for gas. Be sure to smell next to

the oor because some gas is heavier than air and will settle on the oor.

WHAT TO DO IF YOU SMELL GAS

• Do not try to light any appliance.

• Do not touch any electric switch; do not use any phone in your building.

• Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s

instructions.

• If you cannot reach your gas supplier, call the re department.

C. Use only your hand to turn the gas shutoff valve. Never use tools. If the valve will not turn by

hand, don’t try to repair it, call a qualied service technician. Force or attempted repair may result

in a re or explosion.

D. Do not use this appliance if any part has been under water. Immediately contact a qualied

installer or service agency to replace a ooded water heater. Do not attempt to repair the unit! It

must be replaced!

1. STOP! Read the safety information above on this label.

2. Turn off all electric power to the appliance.

3. Do not attempt to light the burner by hand.

4. Turn the gas shutoff valve located on the outside of the unit to the closed position.

5. Wait ve (5) minutes to clear out any gas. If you then smell gas, STOP! Follow “B” in the

safety information above on this label. If you don’t smell gas, go to the next step.

6. Turn the gas shutoff valve located on the outside of the unit to the open position.

7. Turn on all electrical power to the appliance.

8. If the appliance will not operate, follow the instructions in “To Turn Off Gas to Appliance,” and

call your service technician or gas supplier.

1. Turn off all electric power to the appliance if service is to be performed.

2. Turn the gas shutoff valve located on the outside of the unit to the closed position.

FOR YOUR SAFETY READ BEFORE OPERATING

OPERATING INSTRUCTIONS

TO TURN OFF GAS TO APPLIANCE

40 Page

Operang Safety

Owner's Guide

A pressure relief valve listed as complying with the standard for Relief Valve and Automatic Gas Shutoff

Devices for Hot Water Supply System, ANSI Z21.22

・

CSA 4.4, shall be installed at the time of installation

of the water heater in the location specied by the manufacturer. Local codes shall govern the installation of

relief devices for safety operation of the water heater. The relief valve must not be removed or plugged.

No valve shall be placed between the relief valve and the water heater. The relief from the discharge of

the pressure relief valve shall be disposed of in a suitable place where it will cause no damage. Also, there

shall be no other reducing coupling or other restrictions installed on the discharge line to restrict ow.

See Installation Manual heading “PRESSURE RELIEF VALVES” for installation and maintenance of relief

valve discharge line and other safety precautions.

Vapors from ammable liquids will explode and catch re causing death or severe burns.

Do not use or store ammable products such as gasoline, solvents or adhesives in the same room or

area near the water heater.

Keep ammable products:

1. Far away from heater.

2. In approved containers.

3. Tightly closed and out of reach of children.

4. Water heater has a main burner, which may

come on at any time and will ignite ammable

vapors.

Vapors:

1. Cannot be seen.

2. Are heavier than air.

3. Go a long way on the oor.

4. Can be carried from other rooms to the main

burner by air currents.

Do not install water heater where ammable products will be stored or

used unless the main burner is at least 18” above the oor. This

will reduce, but not eliminate the risk of vapors being ignited by the

main burner.

Read and follow water heater warnings and instructions. If the owner’s

manual is missing, contact the retailer or manufacturer.

Flammable Vapors

FLAMMABLES

1. Water temperature over 125°F (52°C) can cause severe burns instantly or death from

scalds.

2. Children, disabled and elderly are at highest risk of being scalded.

3. Feel water before bathing or showering.

4. Temperature limiting valves are available. See manual.

5. The outlet temperature of the water heater is set at 120°F (50°C). If you require water temperatures

below this setting, follow the instruction manual.

6. Use this heater at your own risk. Test the water before bathing or showering. Do not leave children or

an inrm person unsupervised. See your local water supply company [plumbing hardware retailer] for

temperature limiting valves that are available.

BRÛLURE

BURN

CHAUDECHAUDE

HOTHOT

CHAUDE

HOT

DANGER

41 Page

NORMAL OPERATION

GENERAL

• When the remote controller is installed, it will take priority over the built-in controller.

• The controller has an energy saving mode. Five minutes after the water heater stops

operating, the backlight of the controller turns off.

• The backlight of the remote will turn back on once the water heater begins firing again.

1. Open a cold water

fixture.

2. Mix hot water with the cold water

to get the correct temperature water.

3. When finished, close the

water fixture.

• Flow rate to activate the water heater: 0.5 gallon per minute at the default set

temperature (1.9 L/min).

• Flow rate to keep the water heater running: 0.4 gallon per minute (1.5 L/min).

NOTICE

Normal Operaon

Owner's Guide

BUILT-IN CONTROLLER and REMOTE CONTROLLER

The illustraons below show examples of the displays of the controller. The exact display may dier

from examples.

"COLD" Button

"HOT" Button

Press the "HOT" button or the "COLD"

button to set the hot water temperature.

STAND BY LED (Orange)

The indicator is ON to show that

power is ON.

IN USE LED (Green)

The indicator lights during combustion.

"INFO" Button

Each time the button is pressed,

the operation mode is selected

in the sequence of the following.

Inlet water

temperature

Outlet water

temperature

Water

flow

When the STAND BY LED is ON, the

hot water temperature will be

displayed.

Display for Temperature

"ON/OFF" Button

Press this button to

start or stop operation.

Built-in controller

Remote controller

Temperature above 125 °F (52 °C) can cause severe burns or death from scalding.

Children, disabled and the elderly are at high risk of being injured.

WARNING

42 Page

TEMPERATURE SETTINGS

-Set temperature-

Normal Operaon

Owner's Guide

Operation

Screen on the controller

Built-in controller Remote controller

Turn on the 120 VAC power supply to the unit (the water

heater or the multi-unit controller).

Press the "ON/OFF" button on the controller in order to

turn the controller on.

When ON, the STAND BY LED is lit.

It shows the set temperature on its display as shown in

the picture on the right. (EX.: 120 °F)

Press the "HOT" button or the "COLD" button to set the

temperature setting of the unit.

Increasing temperature from 120 °F (50 °C) to 125 °F (52 °C) :

1. The water heater must be in Stand By to increase the

temperature.

2. Press the "HOT" button to set 120 °F (50 °C).

3. Press and hold the "INFO" button and the "HOT"

button for at least 3 seconds. The remote will emit a

beep and change to 125 °F (52 °C).

4. To increase the set temperature further, press the

"HOT" button. You can increase the temperature

setting up to 140 °F (60 °C).

Increasing temperature above 140 °F (60 °C)

-510C model only-:

1. The water heater must be in Stand By to increase the

temperature.

2. Press the "HOT" button to set 140 °F (60 °C).

3. Press and hold the "INFO" button and the "HOT"

button for at least 3 seconds. The remote will emit a

beep and change to 145 °F (63 °C).

4. To increase the set temperature further, press the

"HOT" button. You can increase the temperature

setting up to 160 °F (70 °C).

(EX.: 120 °F)

°F 100 105 110 115 120* 125 130 135 140

°C 38 40 43 45 50* 52 55 57 60

a) For 110U (AT-KJr3U-IN/OS) and 310U (AT-K5U-IN/OS)

°F 100 105 110 115 120* 125 130 135 140 145 150 155 160

°C 38 40 43 45 50* 52 55 57 60 63 65 68 70

b) For 510U (AT-D3U-IN/OS)

*Factory setting (Default): 120 °F

Following are the temperature set points that are available with your built-in controller or remote

controller:

-Temperature table of controller-

43 Page

-Addional features-

Informaon mode

You can get some information about the water heater's condition by pressing the "INFO" button. For

more information, follow the procedures below:

The controller has a function that can change units of temperature and flow rate from °F to °C and from

gallon per minute to liter per minute and vice versa. Please follow the procedures below:

Unit conversion mode

INFO

Button

Operation

Screen on the controller

Built-in controller Remote controller

1st. press

Inlet water temperature will be displayed on

the remote controller by pressing the "INFO"

button.

2nd. press

Outlet water temperature will be displayed on

the remote controller by pressing the "INFO"

button.

3rd. press

Water flow will be displayed on the remote

controller by pressing the "INFO" button.

4th. press

Press the "INFO" button to finish information

mode.

Inlet water

temperature

Outlet water

temperature

Water flow

Normal Operaon

Owner's Guide

Operation

Screen on the controller

Built-in controller Remote controller

Press the "ON/OFF" button on the controller in

order to turn the controller on.

When ON, the orange LED is lit.

The previous set temperature will be displayed on

the screen.

Press the "INFO" button for at least 3 seconds.

The set temperature should now be displayed in the

alternate unit of measurement.

(EX.: 100 °F)

(EX.: 38 °C)

44 Page

TEMPERATURE SETTINGS ON THE PCB

WITHOUT CONTROLLER

There are two preset temperatures, 120 °F (50 °C) and 140 °F (60 °C), that you can select by changing the

DIP switch settings on the computer board without the controller. See the table below.

When the controller is in normal operation, the set temperature of the controller is given priority over the

set temperature of the DIP switch settings.

NOTE: The tables above show the correct DIP switch position for each temperature setting.

(Each black square represents a switch.) For the 110U (AT-KJr3U-IN/OS) and 310U (AT-K5U-

IN/OS), only adjust DIP switch No. 9. For the 510U (AT-D3U-IN/OS), only adjust DIP switch

No. 5 on the lower bank. Do not adjust the other DIP switches for temperature adjustment.

WARNING

• DO NOT adjust the upper bank of DIP switches for the 510U (AT-D3U-IN/OS).

• Turn off the power supply to the water heater before changing the DIP switch

settings.

• The temperature has been preset at the factory to 120 °F (50 °C).

DIP switches

Computer board

110U (AT-KJr3U-IN/OS)and 310U (AT-K5U-IN/OS)

120 °F (50 °C)

DEFAULT

140 °F (60 °C)

No. 9 : OFF

No. 9 : ON

OFF

1 2 3 4 5 6

7 8 9

OFF

1 2 3 4 5 6 7 8 9 10

Lower bank of

DIP switches

Computer board

Upper bank of

DIP switches

(Lower bank of DIP switches)

120 °F (50 °C)

DEFAULT

140 °F (60 °C)

No. 5 : OFF No. 5 : ON

510U (AT-D3U-IN/OS)

OFF

1 2 3 4 5 6

OFF

1 2 3 4 5 62 3 4 5 6

Normal Operaon

Owner's Guide

45 Page

FLOW

• This unit comes equipped with heating blocks to protect it against damages associated with freezing.

• For this freeze protection system to operate, there has to be electrical power to the unit. Damage

to the heat exchanger caused by freezing temperatures due to power loss is not covered under the

warranty. In cases where power losses can occur, consider the use of a backup power supply.

• The freeze protection system will activate when the air temperature inside the case or water in the heat

exchanger is less than 36.5 °F (2.5 °C).

• In any areas subject to freezing temperatures, the manufacturer highly recommends an indoor instal-

lation with an indoor model. In such an installation, freezing issues can occur if cold air enters through

the venting into the heat exchanger, whether by negative pressures within the installation location or

by strong outside winds.

• The manufacturer also highly recommends the use of a backflow preventer (sold separately)

to minimize the amount of cold air entering through the exhaust venting when the water heater is off.

• It is the installer’s responsibility to be aware of freezing issues and take all preventative measures. The

manufacturer will not be responsible for any damage to the heat exchanger as a result of freezing.

• If you will not be using your heater for a long period of time:

1. Completely drain the water out of the unit. Refer to p. 46.

2. Disconnect power to your heater.

This will keep your unit from freezing and being damaged.

Appliance/Use

Flow rate

GPM (US) L/min

Lavatory Faucet 1.0 3.8

Bath Tub 4.0 – 10.0 15.2 - 37.8

Shower 2.0 7.5

Kitchen Sink 1.5 5.6

Dishwasher 1.5 5.6

Washing machine 4.0 15.2

Household Flow Rates

Taken from UPC 2006

• The flow rate through the water heater is limited

to a maximum of 6.6 GPM (25 L/min) for the 110U

model, 8.0 GPM (30 L/min) for the 310U model,

and 10.0 GPM (38 L/min) for the 510U model.

• The temperature setting, along with the supply

temperature of the water, will determine the flow

rate output of the unit.

• Please refer to the temperature vs. gallons per

minute charts on p. 60 to determine the likely flow

rates based on your local ground water temperature

and your desired outlet water temperature.

• Based on the United States Department of Energy

method of testing water heater output, the water

heater is rated for gallons per minute (GPM) (liters

per minute (L/min)) for Natural Gas and Propane,

when raising the water temperature by 77 °F (43 °C)

(from 58 °F to 135 °F (14 °C to 57 °C)).

See the chart on the right.

• Refer to the table to the top right for typical

household plumbing fixture flow rates to determine

what the water heater can do in a household

application.

Only pipes within the water heater are protected by the freeze protection system.

Any water pipes (hot or cold) located outside the unit will not be protected.

Properly protect and insulate these pipes from freezing.

CAUTION

FREEZE PROTECTION SYSTEM

Unit: GPM (L/min)

Model Flow rate

110U

Indoor

3.0 (11.4)

Outdoor

310U

Indoor

4.1 (15.5)

Outdoor

510U

Indoor

4.2 (15.9)

Outdoor

Normal Operaon

Owner's Guide

46 Page

UNIT DRAINING and FILTER CLEANING

MAINTENANCE AND SERVICE

• Clean the cold-water inlet filter. (Refer to "Unit Draining and Filter Cleaning" on this page.)

• Be sure that all openings for combustion and ventilation air are not blocked.

• The venting system should be checked annually for any leaks, corrosion, blockages or damage.

• The burner should be checked annually for dust, lint, grease or dirt.

• Keep the area around the water heater and terminations clear. Remove any combustible materials, gasoline,

flammable vapors, and liquids.

• In accordance with all local codes and common safety practices, water discharged from the pressure relief valve

can cause severe burns instantly from scalding. DO NOT touch the pressure relief valve.

• If the relief valve discharges periodically, it may be due to thermal expansion in a closed water supply system.

Contact the water supplier or local plumbing inspector on how to correct this situation.

• Visual check of burner flames (see below) through the burner window in the burner assembly located at the

middle of the water heater.

The manufacturer recommends having the unit checked once a year or as necessary by a licensed technician. If

repairs are needed, any repairs should be done by a licensed technician.

Turn off the electrical power supply and close the manual gas shutoff valve

and the manual water control valve before servicing.

WARNING

1. Close the manual gas shutoff valve.

2. Turn off power to the unit and wait a couple of seconds. Turn

on again.

3. Wait 30 seconds, and then turn off power to the unit.

4. Close the inlet water shutoff valve.

• If the heater is part of an Easy-Link or Multi-Unit System,

close the inlet and outlet shutoff valves to isolate the

heater. Then proceed to step 6.

5. Open all hot water taps in the house. When the residual

water flow has ceased, close all hot water taps.

6. Have a bucket or pan to catch the water from the unit’s drain

plugs. If Isolation valves are installed, open the drains to

drain the water. If isolation valves are not installed, unscrew

the two drain plugs (large and small) to drain the water out

of the unit. Do not lose the o-rings that will be on the two

drain plugs.

7. Wait a few minutes to ensure all water has completely

drained from the unit.

8. Clean the filter: Check the water filter located within the

cold inlet. With a tiny brush, clean the water filter of any

debris which may have accumulated and reinsert the filter

back into the cold water inlet.

9. Securely screw the drain plugs back into place.

Hand- tighten only.

Normal Operaon

Owner's Guide

Sasfactory

Blue ame

Unsasfactory

Flame liing

above the

burner

Unsasfactory

Red or Yellow

ame

Inlet

water valve

Drain plug

(Small)

Outlet

water valve

Drain plug with Filter (Large)

47 Page

TROUBLESHOOTING

GENERAL

PROBLEM SOLUTIONS

TEMPERATURE and AMOUNT OF HOT WATER

It takes a long time to

get hot water at the

fixtures.

• The time it takes to deliver hot water from the water heater to your

fixtures 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 fixtures quicker, you may

want to consider a hot water recirculation system. (p. 35)

The water is not hot

enough.

• Compare the flow and temperature. See the charts on p. 60.

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

• Is the gas supply valve fully open? (p. 37)

• Is the gas line sized properly? (p. 26)

• Is the gas supply pressure within specified limits? (p. 26)

• Is the set temperature set too low? (pp. 42 and 44)

• Is the Easy Link or Multi-Unit system set up correctly?

The water is too hot. • Is the set temperature set too high? (pp. 42 and 44)

The hot water is not

available when a

fixture is opened.

• Make sure the unit has 120 VAC, 60 Hz power supply.

• Is the power button on the controller or inside the water heater turned

on?

• Is the gas supply valve fully open? (p.37)

• Is the water supply valve fully open? (p. 37)

• Is the filter on the cold water inlet clean? (p. 46)

• Is the hot water fixture sufficiently open to draw at least 0.5 GPM

(1.9 L/min) through the water heater? (p. 41)

• Is the unit frozen? (p. 45)

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

• Is the Easy Link or Multi-Unit system set up correctly?

The hot water turns

cold and stays cold.

• Is the flow rate enough to keep the water heater running? (p. 41)

• If there is a recirculation system installed, does the recirculation line have

enough check valves? (p. 35)

• Is the gas supply valve fully open? (p. 37)

• Is the filter on the cold water inlet clean? (p. 46)

• Are the fixtures clean of debris and obstructions?

Fluctuation in hot

water temperature.

• Is the filter on the cold water inlet clean? (p. 46)

• Is the gas line sized properly? (p. 26)

• Is the supply gas pressure within specified limits? (p. 26)

• Check for cross connection between cold water lines and hot water lines.

• Is the Easy Link or Multi-Unit system set up correctly?

Troubleshoong

Owner's Guide

48 Page

PROBLEM SOLUTIONS

WATER HEATER

Unit does not ignite

when water goes

through the unit.

• Is the flow rate over 0.5 GPM (1.9 L/min)? (p. 41)

• Check the filter on the cold water inlet. (p. 46)

• Check for reverse connection and cross connection.

• If you use the remote controller, is the power button turned on?

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

the set temperature, the water heater won't work.

• Is the gas supply turned on?

• Is power available to the unit? If so, is the power button on the

controller or inside the water heater turned on?

The fan motor is

still spinning after

operation has stopped.

• This is normal. After operation has stopped, the fan motor keeps

running from 15 to 70 seconds in order to re-ignite quickly, as well

as purge all the exhaust gas out of the flue.

Unit sounds abnormal

while in operation

• Contact the manufacturer at 1-877-737-2840.

Buit-in controller

and remote controller

Built-in and remote

controller do not

display anything when

the power button is

turned on.

• Make sure the unit is supplied with power.

• For the remote controller: Make sure the connection to the unit is

correct. (pp. 30 and 31)

When the

controller turned

ON, STAND BY LED

is lit.

Buit-in controller

• When the unit has not operated for five minutes or more, the

display turns off to conserve energy.

• Although the controller of the parent unit will display the set

temperature at the Easy-Link System, the controller of the child

unit will not display the set temperature.

An ERROR code is

displayed.

• Please see pp. 49 to 52.

EASY-LINK SYSTEM

510U model only

How are the unit

numbers assigned?

• For an Easy-Link System, the Parent unit is always labeled #1 and all

other subsequent Child units are numbered randomly.

• To check which numbers are assigned to which Child units, push the

button on the computer board of any Child unit as shown below.

The unit number will be displayed on the controller of each Child

unit. (Refer to p. 33.)

Buon to check unit numbers

Troubleshoong

Owner's Guide

49 Page

Troubleshoong

Owner's Guide

Error code

ERROR CODES

-General-

• The units have self-diagnostic functions for safety and convenience when troubleshooting.

• If there is a problem with the installation or the unit, the error code will be displayed on the built-in

controller or remote controller.

• Consult the table on the following pages for the description of each error code.

-Single unit Installaons-

Example: If your unit has the “321” error code (which signifies an inlet thermistor failure)

• Indicator on the built-in controller

and/or remote controller: “321” will be displayed

on the screen in its entirety.

• Green LED on the computer board: The green LED on the computer board will indicate this code with

two flashes every 1/2 second. The pattern will repeat with a three second delay between patterns.

Error code Green LED

on on on on

on on

oﬀ oﬀ oﬀ oﬀ oﬀ

321

Error Indication

Green LED ashes error code

110U and 310U

(AT-KJr3/K5-IN/OS)

510U (AT-D3U-IN/OS)

Error code indicator on

the built-in controller

Error code indicator on

the remote controller

Error Code

on the temperature

controller

Green LED

The number

of ﬂashes

Flash paern

031 701 711

One

311 321 331

391 441

Two

111 121

Three

611 651 661

Four

101 991

Five

510 551 721

Six

on on

oﬀ

0.5 sec. on, O.5 sec. oﬀ 3 sec. oﬀ

50 Page

-For the 510U (AT-D3U-IN/OS) model in an Easy-Link System-

Error codes will be displayed differently with units installed within an Easy-Link 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 of "321" is displayed in an Easy-Link System.

Example: If Unit #2 has the “321” error code (inlet thermistor failure)

• Indicator on the built-in controller

and/or remote controller of Parent unit:

“321” and "2" will intermittently flash on

the display.

Unit #Error code

9009069005 (TM-RE42)

Unit #1

PARENT

Unit #2

CHILD

Unit #4

CHILD

Unit #3

CHILD

9009069005 (TM-RE42)

Unit #1

PARENT

Unit #2

CHILD

Unit #4

CHILD

Unit #3

CHILD

Error code Green LED

on on on on

on on

oﬀ oﬀ oﬀ oﬀ oﬀ

321

Green LED on

the computer board

Outdoor model installation

• Unit #2:

The green LED on the computer board will be

flashing twice, just like in the single unit example.

• Unit #3 and #4:

The green LED on the computer board will stay off.

Indoor model installation

• Unit #2:

"321" will intermittently flash on

the display. The green LED on

the computer board will be flashing

twice, just like in the single

unit example.

• Unit #3 and #4:

These units will not display anything,

as the error code does not pertain to them.

51 Page

-Fault Analysis of Error Codes-

If the error code is displayed on the computer board of the water heater or the controller, please check

the following. After checking, consult with the manufacturer.

Troubleshoong

Owner's Guide

Remote

Green

LED

Malfunction

description

Diagnosis

031

One Flash

Incorrect DIP switch

setting

• Check the DIP switch settings on the PCB (Part #701).

101

Five Flashes

Warning for the “991”

error code

• Check the gas type of the water heater.

• Check if there is any blockage in the intake air and/or

exhaust.

• Check if there is enough distance between the exhaust

and air intake terminals.

• Check the altitude/elevation of area of where the water

heater is installed.

• Check if there is grease and/or dirt in the burner (Part #101)

and the fan motor (Part #103), especially if the water heater

has been installed in a contaminated area.

111*

Three Flashes

Ignition failure • Check if the Hi-limit switch (Part #412) is properly

functioning.

• Check for connection/breakage of wires (Part #008, 413, 708,

709), burn marks on the computer board (Part #701), and/or

soot on the flame rod (Part #107) and the ignitor (Part #108).

• Ensure that the gas supply is turned on. If your water

heater has been properly converted to use propane,

ensure that the tank is not empty.

• Check if there is a buzzing spark ignition sound coming

from the burner (Part #101) when water heater prepares

for combustion.

• Listen for the double “clunk” sound coming from the gas

valve assembly (Part #102) when the water heater goes

into combustion.

• Check if there is leaking from heat exchanger (Part #401).

121*

Three Flashes

Loss of flame • Check if the Hi-limit switch (Part #412) is properly

functioning.

• Check for connection/breakage of wires (Part #008, 413,

708, 709), burn marks on the computer board (Part #701),

and/or soot on the flame rod (Part #107) and the ignitor

(Part #108).

• Ensure that the gas supply is turned on. If your water

heater has been properly converted to use propane,

ensure that the tank is not empty.

• Check if there is leaking from the heat exchanger (Part #401).

311*

Two Flashes

110U & 310U:

Outlet thermistor

failure

510U:

Heat exchanger

thermistor failure

• Check for connection/breakage of wires and/or debris on

the thermistor (Part #407, 408, 411, 713).

321*

Two Flashes

Inlet thermistor failure

331*

Two Flashes

Outlet thermistor

failure

(510U model only)

391

Two Flashes

Air-fuel ratio rod failure • Check for connection/breakage of wires (Part #709) and/

or soot on the AFR rod (Part #107).

441

Two Flashes

Flow sensor failure

(Only Easy-Link &

Multi-Unit System)

• Check for connection/breakage of wires and/or debris on

the flow sensor impeller (Part #402).

• Check water filter. Ensure isolation valves are open.

52 Page

Troubleshoong

Owner's Guide

Remote

Green

LED

Malfunction

description

Diagnosis

510

Six Flashes

Abnormal main gas

solenoid valve

• Check for connection/breakage of wires (Part #708) and/

or burn marks on the computer board (Part #701).

551

Six Flashes

Abnormal gas

solenoid valve

• Check for connection/breakage of wires (Part #714) and/

or burn marks on the computer board (Part #701).

611*

Four Flashes

Fan motor fault • Check for connection/breakage of wires, dust buildup

in the fan motor (Part #103) and/or burn marks on the

computer board (Part #701).

• Check for frozen/corrosion of connectors (Part #103).

651*

Four Flashes

Flow adjustment

valve fault (Only

Easy-Link & Multi-Unit

System)

• Inspect the flow adjustment valve (Part #402), for

connection/breakage of wires, locked motor drive due to

scale buildup, and/or water leakage.

661*

Four Flashes

Bypass valve fault

(510U model only)

• Inspect the bypass valve (Part #403), for connection/

breakage of wires, locked motor drive due to scale

buildup, and/or water leakage.

701*

One Flash

Computer board fault • Check the outlet thermistor (Part #408) as it may need to

be cleaned.

• Check for connection/breakage of wires (Part #714).

711*

One Flash

Gas solenoid valve

drive circuit failure

• Refer to the 111 and 121 error codes.

721*

Six Flashes

False flame detection • Check if condensate drain is installed on the vent collar of

the water heater.

• Check if there is leaking from heat exchanger (Part #401).

741

N/A

Miscommunication

between water heater

and remote controller

• Inspect the connections between the water heater and

remote controller.

• Check the power supply of the water heater.

751

N/A

Miscommunication

between water heater

and built-in controller

• Inspect the connections between the water heater and

built-in controller.

• Check the power supply of the water heater.

761

N/A

Miscommunication in

Easy-Link system

• Check if the connections between the parent unit and the

child units are correct. Refer to p. 33.

• Verify that each unit has power and that its power switch

above the computer board is in the ON position.

991

Five Flashes

Imperfect

combustion

• Check the gas type of the water heater.

• Inspect the environment around the water heater.

Determine how long the unit has been installed.

• Check the altitude/elevation of the area of where the

water heater is installed.

• Check if there is any blockage in the intake air and/or

exhaust.

• Check whether there is enough distance between the

exhaust and air intake terminals.

• Check if there is grease and/or dirt in the burner (Part

#101) and the fan motor (Part #103), especially if the

water heater has been installed in a contaminated area.

*These error codes will be cleared when water flow stops.

53 Page

COMPONENTS DIAGRAM

Components Diagram

Owner's Guide

Case assembly

006

004

052

003

052

003

001

005

007

715

002

052

050

704

052

050

704

710

008

002

Built-in temperature controller

722

721

065

54 Page

510U (AT-D3U-IN/OS)

110U (AT-KJr3U-IN/OS) and

310U (AT-K5U-IN/OS)

701

705

103

402

707

713

403

714

709

708

711

705

103

709

402

711

707

714

407

408

708

701

064

713

712

721

Computer board assembly

Surge box assembly

Components Diagram

Owner's Guide

120

705

053

062

706

703

068

704

705

716

55 Page

Components Diagram

Owner's Guide

Burner assembly

153

154

103

401

103

054

118

053

105

106

112

708

401

150

117

116

121

062

114

701

102

119

101

107

707

152

151

057

063

062

067

062

055

056

052

055

053

111

113

061

110

711

714

053

057

060

109

115

054

702

053

108

104

122

104

053

052

709

Manifold

assembly

Burner

assembly

Exhaust section (Outdoor model)

LP Conversion Kit

130

131

510U (AT-D3U-IN/OS)

56 Page

Components Diagram

Owner's Guide

Water Way assembly

458

462

403

456

460

411

459

454

413

450

463

452

059

412

414

453

066

462

417

461

401

460

456

458

414

416

451

414

451

402

404

407406

405

460

456

458

461

052

415

058

454

457

052

408

410

409

415

058

454

455

052

401

To Water

inlet secon

To Water

outlet secon

458

462

414

451

414

052

To Water

inlet secon

To Water

outlet secon

Bypass secon

510U (AT-D3U-IN/OS)

Water outlet section

Water inlet section

110U 310U

(AT-KJr3U AT-K5U-IN/OS)

510U (AT-D3U-IN/OS)

57 Page

Parts List

Owner's Guide

PARTS LIST

Item # Description

Part #

110U, 310U and

510U models

AT-KJr3U-IN/OS,

AT-K5U-IN/OS and

AT-D3U-IN/OS

001 Case assembly for Indoor models

for Outdoor models

N/A

EK596

EK597

002 Front cover for Indoor models

for Outdoor models

N/A

EK598

EK599

003

004

005

006

007

008

Bracket

Intake air port assembly

Junction box

Power supply cord assembly

Back guard panel

Overheat-cut-off fuse for combustion chamber

N/A

319143-510

319143-437

N/A

319143-016

EK455

EK600

EK190

EKK4D

EK601

EM484

050

051

052

053

Truss screw M4×12 (W/Washer) SUS410

Truss screw M4×10 (W/Washer) SUS410

Truss screw M4×10 (Coated) SUS3

Truss screw M4x10 SUS

319143-025

319143-325

319143-026

319143-060

EW000

EW001

EW002

EW003

054

055

056

057

Hex head screw M4×12 (W/Washer) SUS3

Hex head screw M4x8 FEZN

Pan screw M4x10 FEZN

Pan Screw M3x10 SUS

319143-326

319143-063

319143-062

319143-327

EW004

EW005

EW006

EW008

058

059

060

061

062

063

Tapping screw M4x6 SUS3 Truss head

Tapping screw M3x6 SUS3 Pan head

Screw M3x6 SUS3 Binding head

Pan screw M4x8 MFZN

Tapping screw M4x14 SUS410 Truss head

Screw M3x12 BSNI Raised counter sunk head

319143-328

319143-087

320273-330

319143-059

320273-491

319143-331

EW009

EW00A

EW00B

EW00D

EW00E

EW00X

064

065

066

067

068

Screw M3x6 BSNI Binding head

Pan screw M4x20 SUS410

Truss screw M4x8 SUS3

Tap tight screw M4x12 FEZN

Truss screw M4x10 MFZN3

319143-439

N/A

319143-201

319143-372

EW016

EW018

EW02A

EKK31

EX014

101

102

Burner assembly

Manifold with gas valve assembly NA

319143-555

319143-556

EK554

EK555

103 Fan motor for Indoor models

Fan motor for Outdoor models

319143-443

319143-043

EK109

EKK25

104 Fan motor plate for Indoor models

Fan motor plate for Outdoor models

319143-282

319143-453

EM381

EK140

105

106

107

108

109

110

Burner window

Rod holder gasket

Flame rod with AFR function

Igniter rod

Rod holder

Rod cap

320273-625

319143-560

319143-561

319143-562

319143-563

320273-358

EKN58

EK559

EK560

EK561

EK562

EK462

111

112

113

Burner damper

Manifold gasket A

Manifold gasket B

100270556

319143-565

319143-566

EK602

EK564

EK565

114

115

116

117

Pressure port

Combustion chamber tube

Gas inlet

Gas inlet ring

319143-042

319143-344

319143-050

319143-049

EKK2D

EX019

EKK1E

EKK2Z

58 Page

Item # Description

Part #

110U, 310U and

510U models

AT-KJr3U-IN/OS,

AT-K5U-IN/OS and

AT-D3U-IN/OS

118

119

Burner gasket

Burner holder gasket

319143-568

319143-569

EK567

EK568

120

121

122

Surge box plate

PCB fixing plate

Thermostat

319143-176

N/A

319143-185

EK436

EK603

EKJ59

130

131

LP Conversion kit

Manifold gasket

100270585

319143-581

EK604

EK592

150

151

152

153

154

O-ring P18 NBR (Manifold)

O-ring P20 NBR (Black)

Silicon ring for Outdoor models

Rain protection plate in Exhaust chamber for Outdoor models

Exhaust port for Outdoor models

N/A

319143-057

319143-206

319143-216

319143-219

EK570

EK042

EKK3G

EKK53

EKK56

401 Heat exchanger assembly for 110U and 310U Indoor

(AT-KJr3U-IN and AT-K5U-IN)

for 110U and 310U Outdoor

(AT-KJr3U-OS and AT-K5U-OS)

for 510U Indoor (AT-D3U-IN)

for 510U Outdoor (AT-D3U-OS)

100270557

100270558

100270559

100270560

EK605

EK606

EK607

EK608

402

403

404

405

406

Flow adjustment valve / Flow sensor

Bypass valve for 510U (AT-D3U-IN/OS) model

Water inlet

Inlet drain plug

Inlet water filter

319143-463

319143-464

319143-193

319143-197

319143-198

EK129

EKD58

EKK1U

EKK2B

EKK2C

407 Inlet thermistor for 110U (AT-KJr3U-IN/OS) and 310U (AT-K5U-IN/OS)

Inlet thermistor for 510U (AT-D3U-IN/OS)

319143-214

319143-572

EKK4J

EK573

408 Outlet thermistor for 110U (AT-KJr3U-IN/OS) and 310U (AT-K5U-IN/OS)

Outlet thermistor for 510U (AT-D3U-IN/OS)

319143-529

319143-573

EK207

EK574

409

410

411

Water outlet

Outlet drain plug

Heat exchanger thermistor for 510U (AT-D3U-IN/OS) model

319143-466

319143-079

319143-574

EK104

EK239

EK575

412 Hi-Limit switch for 110U (AT-KJr3U-IN/OS) and 310U (AT-K3U-IN/OS)

Hi-Limit switch for 510U (AT-D3U-IN/OS) model

319143-228

319143-095

EM212

EKN34

413

414

415

416

417

Overheat-cut-off fuse for heat exchanger

Pipe heater

Inlet heater

Pipe inlet

Joint outlet

319143-067

319143-531

319143-468

100270581

319143-576

EX02A

EK209

EK105

EK609

EK577

450

451

452

453

Fuse fixing plate 40

Heater fixing plate 16

Fuse fixing plate 18

Pipe heater fixing plate

N/A

319143-125

N/A

EK616

EK031

EK476

EK610

454

455

456

457

O-ring P4 FKM

O-ring P6 FKM

O-ring P14 FKM

O-ring P15 FKM

319143-082

319143-080

319143-100

319143-091

EZM04

EZM06

EZM14

EZM15

458

459

460

461

O-ring P16 FKM

Fastener “4-11” for 510U (AT-D3U-IN/OS) model

Fastener “14-22”

Fastener “16A”

319143-083

319143-097

319143-105

319143-226

EZM16

EKH30

EKK24

EM192

462

463

Fastener “16-25A”

Silicon ring for Indoor models

319143-205

319143-065

EKK39

EKN50

Parts List

Owner's Guide

59 Page

Item # Description

Part #

110U, 310U and

510U models

AT-KJr3U-IN/OS,

AT-K5U-IN/OS and

AT-D3U-IN/OS

701 Computer board for 110U (AT-KJr3U-IN/OS) model

for 310U (AT-K5U-IN/OS) model

for 510U (AT-D3U-IN/OS) model

100270582

100270583

100270584

EK611

EK612

EK613

702

703

704

Remote fixing plate for 510U (AT-D3U-IN/OS)

Surge box

120 VAC wire for Indoor models

for Outdoor models

319143-484

320273-128

319143-427

319143-138

EK152

EK280

EK146

EKK3C

705

706

Switch wire

120 VAC Power ON-OFF switch

N/A

EK614

EK590

707

708

Remote controller wire for 110U (AT-KJr3U-IN/OS) and 310U (AT-K5U-IN/OS)

for 510U (AT-D3U-IN/OS)

Gas valve wire

319143-490

319143-491

N/A

EK189

EK165

EK585

709

710

711

Flame rod wire

Cable strap

Igniter assembly

N/A

319143-425

319143-479

EK586

EW022

EK153

712

713

714

715

716

Computer board cover

24V cables for 510U (AT-D3U-IN/OS)

Proportional gas valve wire

Rubber grommet for Indoor models

Surge box cover

319143-274

N/A

319143-481

319143-426

N/A

EM329

EK587

EK112

EK184

EK615

721

722

Temperature controller

Controller fixing plate

319143-502

N/A

EK173

EK588

N/A Communication cable for linking 320273-585 EKK0J

Parts List

Owner's Guide

60 Page

OUTPUT TEMPERATURE CHART

Chart is based on properly sized gas line

110U (AT-KJr3U-IN/OS)

Output Temperature Chart

Owner's Guide

*When the set temperature is 130 °F (55 °C) or higher, maximum flow rate is limited to 8.0 GPM.

Output Temperature vs. GPM (Max. 6.6 GPM) with Various Inlet Water Temperature

Output Hot Water GPM

Set Temp. (°F)

Incoming Temp. (°F)

510U (AT-D3U-IN/OS)

Output Temperature vs. GPM (Max. 10.0 GPM) with Various Inlet Water Temperature

Output Hot Water GPM

Set Temp. (°F)

Incoming Temp. (°F)

310U (AT-K5U-IN/OS)

Output Temperature vs. GPM (Max. 8.0 GPM) with Various Inlet Water Temperature

Output Hot Water GPM

Set Temp. (°F)

Incoming Temp. (°F)

61 Page

1. The manufacturer warrants this product against defects in materials or workmanship as described in this

document if installed within the United States or Canada. The manufacturer or its authorized Service

Representative will, at its sole discretion, repair or replace any failed or defective mechanical or electrical parts,

or components thereof, or, if the manufacturer or its authorized Service Representative cannot replace said

parts, and repair is not commercially practicable, the manufacturer or its authorized Service Representative will

refund the purchase price. The manufacturer or its authorized Service Representative may, at its sole discretion,

use new, refurbished or reconditioned parts.

2. Warranty for all models:

(1) Limited Labor Coverage

• The manufacturer will provide for reasonable labor charges associated with warranty repairs

or replacements within one (1) year from the date of purchase. The manufacturer will only pay

directly to the service provider.

• Warranty service must be performed by an authorized Service Representative. A list of authorized

Service Representatives is available upon request.

• All warranty claims and warranty service must be authorized and approved by the manufacturer.

(2) Includes recirculation and storage tank applications with proper circulation pump control (e.g.

aquastat and/or timer).

- Lack of a proper pump control will reduce the heat exchanger and parts warranty to 3 years.

(3) In all applications, the total of length of operation time must be less than 3,000 hours for the 110U

(AT-KJr3U-IN/OS) and 310U (AT-K5U-IN/OS) models, and less than 9,000 hours for the 510U (AT-D3U-IN/OS) model.

(4) Includes dual-purpose applications (combination heating and domestic)

3. General terms of limited warranty:

This limited warranty gives you specific legal rights, and you may also have other rights which vary from State to

State. The manufacturer will honor the warranty to the original retail buyer at the original location only, within

the United States or Canada, and it is not transferable.

THIS WARRANTY COVERS ONLY FAILED MECHANICAL AND ELECTRICAL PARTS DUE TO FACTORY DEFECTS UNDER

NORMAL USAGE FOR THE PRODUCT’S INTENDED PURPOSES AND WITHIN THE APPLICABLE PERIOD SPECIFIED

IN THE TABLE ABOVE. ONLY DIRECT DAMAGES SHALL BE RECOVERABLE BY A CLAIMANT UNDER THIS LIMITED

WARRANTY AND, IN NO EVENT, WHETHER AS A RESULT OF BREACH OF CONTRACT, BREACH OF WARRANTY,

TORT LIABILITY (INCLUDING NEGLIGENCE), STRICT LIABILITY, INDEMNITY OR OTHERWISE WILL BE LIABLE

FOR ANY SPECIAL, INCIDENTAL, OR INDIRECT CONSEQUENTIAL DAMAGES INCLUDING PROPERTY DAMAGE,

PERSONAL DAMAGES, LOSS OF USE, OR INCONVENIENCE. SOME STATES DO NOT ALLOW THE EXCLUSION OR

LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATION MAY NOT APPLY TO

YOU.

4. Limitation on Duration of Implied Warranties:

ANY IMPLIED WARRANTIES ARISING UNDER STATE LAW, INCLUDING THE IMPLIED WARRANTIES OF FITNESS

FOR A PARTICULAR PURPOSE AND MERCHANTABILITY, SHALL IN NO EVENT EXTEND PAST THE EXPIRATION OF

ANY WARRANTY PERIOD HEREUNDER. SOME STATES DO NO ALLOW LIMITATIONS ON HOW LONG AN IMPLIED

WARRANTY LASTS, SO THE ABOVE LIMITATION MAY NOT APPLY TO YOU.

5. THIS WARRANTY WILL NOT COVER THE FOLLOWING:

• Any product that is not installed by a licensed plumber, gas installer, or contractor.

• Damages due to accidents, abuse, misuse, improper installation, misapplication, or incorrect sizing.

• Damages due to fires, flooding, freezing, electrical surges, or any Acts of God.

• Damages due to unauthorized alterations, attachments, and/or repairs.

• Damages due to a lack of maintenance (e.g. water filter, water treatment system, vent blockage, etc.).

• Any product installed in an improper environment (e.g. corrosive, dusty, chemically contaminated,

excessive lint, etc.).

LIMITED WARRANTY

Warranty

Owner's Guide

Application Type Heat Exchanger Parts Labor

(1)

Single Family Domestic Hot Water 15

(2)(3)

5 1Commercial or Multi-Family Domestic Hot Water 10

(2)(3)

Heating 10

(3)(4)

[Unit: Year]

62 Page

• Freeze damage that occurs without taking proper preventive measures as described in the installation

manual.

• Condensate damage due to improperly installed or lack of a condensate trap (drain).

• Any product not installed in compliance with all applicable local & provincial codes, ordinances, and

good trade practices.

• Any product sold to or installed in areas outside of the fifty states (and the District of Columbia) of

the United States of America and Canada.

• Any product installed in applications that cause the water heater to activate more than 300 times per

day. (This averages to an activation every 5 minutes in a 24-hour period.)

• Any failures that are not due to defects in materials or workmanship (mechanical and/or electrical parts).

• Damages due to improper installation:

• Gas: incorrect gas pipe sizing, incorrect gas meter sizing, incorrect gas type, and/or gas pressures

that fall outside the product’s specified range.

• Water: incorrect water pipe sizing, water pressures that fall outside the product’s specified range,

recirculation flow rates that fall outside the product’s specified range (air removal), and/or lack of

proper methods of air removal in a closed-loop, circulation system. (See installation manual for

details.)

• Electric: supply power voltages that fall outside the product’s specified range.

• Damages due to water quality:

• Introduction of liquids other than potable water into the product.

• Introduction of pool water, spa water, or any chemically treated water into the product.

• Introduction of hard water measuring more than 7 grains per gallon (120 ppm) for single family

domestic applications or more than 4 grains per gallon (70 ppm) for all other types of applications

into the product.

• Introduction of untreated or poorly treated well water into the product.

• Introduction of water with pH levels less than 6.5 and greater than 8.5 into the product.

Warranty

Owner's Guide

63 Page

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1W1101

100269776

AO Smith ATI-310U ProLine XE Ultra-Low NOx Indoor 190,000 BTU Non-Condensing Tankless Water Heater

Product's Documents

Manual - Tankless Non-Condensing Ultra-Low NOx Manual (100269776)

Specifications

AO Smith ATI-310U 200 Questions and Answers