Installa on Instruc ons and
Use & Care Guide
Keep this manual with the heater for future reference whenever maintenance, adjustment or service is required.
Retain your original receipt as proof of purchase.
Read this manual and the labels on the water heater before you install, operate,
or service it. If you have diffi culty following the direc ons, or aren’t sure you
can safely and properly do any of this work yourself:
• Call our Technical Assistance Hotline which is listed on your warranty. We can help you
with installa on, opera ons, troubleshoo ng, or maintenance. Before you call, write
down the model and serial number from the water heater’s ra ng plate.
• Incorrect installa on, opera on, or service can damage the water heater, your house and
other property, and present risks including fi re, scalding, electric shock, and explosion,
causing serious injury or death.
Premium Condensing Residen al
Gas Tankless Water Heaters
Residen al On-Demand Gas Tankless Water Heaters
(X3™ TECHNOLOGY available on some models)
100389043_ 2000628591
March 2025
Do not store or use gasoline or other fl ammable 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 electrical switch; do not use any
phone in your building.
• Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instruc ons.
• If you cannot reach your gas supplier, call the fi re de-
partment.
Installa on and service must be performed by a qualifi ed
installer, service agency or the gas supplier.
WARNING: If the informa on in these instruc ons
is not followed exactly, a fi re or explosion may
result causing property damage, personal injury or
death.
MODELS:
THR-160M, THR-180M, THR-199M
THR-160X3, THR-180X3, THR-199X3
LOW LEAD
C
O
NTENT
2 • Residen al Tankless Gas Water Heater Use and Care Guide
TABLE OF CONTENT
WATER HEATER BASICS ....................................................................................4
COMPONENT VIEW (X3® Model Shown) ..................................................................................................4
TYPICAL INSTALLATIONS (X3® Model Shown) ............................................................................................5
DIMENSIONS .............................................................................................................................................6
SUPPLY CONNECTIONS ..............................................................................................................................7
SPECIFICATIONS .........................................................................................................................................8
IMPORTANT SAFETY INFORMATION .................................................................9
RISKS DURING INSTALLATION AND MAINTENANCE ................................................................................10
RISKS DURING OPERATION ......................................................................................................................10
GETTING STARTED .........................................................................................12
Read Before InstallaƟ on ..........................................................................................................................12
Included Items .........................................................................................................................................14
Available Accessories ..............................................................................................................................15
INSTALLATION................................................................................................17
InstallaƟ on Environment .........................................................................................................................17
Unit Clearances .......................................................................................................................................17
MounƟ ng the Water Heater ...................................................................................................................17
CombusƟ on Air and VenƟ ng InstallaƟ on .................................................................................................18
VenƟ ng ....................................................................................................................................................21
Installing the Vent Pipe ...........................................................................................................................23
Exhaust Vent for Indoor InstallaƟ on ........................................................................................................23
Typical VenƟ ng Confi guraƟ ons: ..............................................................................................................24
Clearances for Sidewall TerminaƟ ons .....................................................................................................28
Clearances for RooŌ op TerminaƟ ons ......................................................................................................29
Exhaust VenƟ ng for Outdoor InstallaƟ on ................................................................................................32
Outdoor Available Accessories ................................................................................................................32
Gas Supply and Gas Pipe Sizing ...............................................................................................................33
Gas Conversion InstrucƟ ons ....................................................................................................................35
Water ConnecƟ ons ..................................................................................................................................35
RecirculaƟ on ...........................................................................................................................................36
CombinaƟ on Potable Water and Space HeaƟ ng .....................................................................................38
Dual Purpose Water HeaƟ ng for the State of MassachuseƩ s .................................................................39
Residen al Gas Tankless Water Heater Use and Care Guide • 3
TABLE OF CONTENTS
X3® Technology .......................................................................................................................................40
Pressure Relief Valve ...............................................................................................................................40
Condensate Drain ....................................................................................................................................41
Printed Circuit Board BaƩ ery ..................................................................................................................42
Electrical ConnecƟ ons .............................................................................................................................42
Cascade System .......................................................................................................................................43
Accessory ConnecƟ ons ............................................................................................................................45
OPERATION ...................................................................................................46
FOR YOUR SAFETY, READ BEFORE OPERATING ........................................................................................ 46
Start-up InstrucƟ ons ................................................................................................................................46
Shut-Down InstrucƟ ons ...........................................................................................................................46
Emergency Shut-Down ............................................................................................................................46
Temperature Adjustment/Seƫ ng the Temperature ................................................................................49
Unit Conversion Mode .............................................................................................................................50
Confi guraƟ on Mode (A Mode) ................................................................................................................51
Confi guraƟ on Mode (C Mode) ................................................................................................................51
Seƫ ng the Clock .....................................................................................................................................52
Seƫ ng RecirculaƟ on Mode and RecirculaƟ on Type ................................................................................53
MAINTENANCE .............................................................................................. 55
Seƫ ng the Pump Timers .........................................................................................................................55
Pump Timer AcƟ vaƟ on ............................................................................................................................56
Regular Maintenance ..............................................................................................................................57
TROUBLESHOOTING .....................................................................................58
Unit Draining & Power Outage
(Freeze ProtecƟ on) .................................................................................................................................58
Condensate Drain ....................................................................................................................................58
Inlet Water Filter .....................................................................................................................................58
General TroubleshooƟ ng .........................................................................................................................59
Error Codes ..............................................................................................................................................60
Fault Analysis of Error Codes ...................................................................................................................60
COMPONENT LIST ..........................................................................................67
FLOW RATE ....................................................................................................73
4 • Residen al Gas Tankless Water Heater Use and Care Guide
WATER HEATER BASICS
X3 Cartridge
Control Display
Printed Circuit Board
Gas Valve
Fan Motor Assembly
Exhaust Port
Inlet Port
Igniter Rod
Flame Sensor
Gas Valve
Venturi Assembly
Flow Sensor Control
Valve Assembly
Igniter
Condensate Trap
Air Pressure Switch
Bypass Valve
Burner Assembly
Pressure Relief Valve
(M Model: Field Supplied)
Pump
Bypass Cartridge
(M Model: Alternative Configuration)
Heat Exchanger
COMPONENT VIEW (X3® Model Shown)
X3® Technology (X3® Model):
This water heater is equipped with X3® Scale Preven on Technology to inhibit scale forma on within the heat exchanger tubing of
this unit. Part of the X3® Technology’s an -scale protec on comes from the special X3® Cartridge media. The X3® Cartridge must
be installed into the manifold located on the underside of the heater cabinet prior to opera on of the unit. X3® Scale Preven on
Technology reduces the forma on of scale in the heat exchanger, extending the opera ng life of the unit in typical potable water
installa ons. Specifi c water condi ons may impact the effi ciency of X3®, such as excessive iron or manganese levels. The maximum
allowable limit of iron is 0.3 mg/l or 0.3 ppm and manganese is 0.05 mg/l or 0.05 ppm. Levels greater than these will reduce
the eff ec veness of the X3. Refer to the guidelines below and consult a water quality expert to determine if your water is within
acceptable X3® and EPA guidelines. NOTE: Pressure Relief Valve supplied in the box with this model.
Bypass Cartridge (M Model):
The Bypass cartridge will come preinstalled from the factory. Please verify the three screws securing the Bypass cartridge are
ghtened, See Figure 34. NOTE: Pressure Relief Valve will need to be fi eld supplied with this model.
Residen al Gas Tankless Water Heater Use and Care Guide • 5
Expansion
Tan k
Outlet Venting
Inlet Air
Pressure Relief Valve
(Drain Line not
shown for clarity)
Water Shutoff Valve
Water
Shutoff
Valve
HWS
CWS
Drip Leg
Gas Line
Gas
Shutoff Valve
NOTE: Condensate Drain not shown for clarity.
CWS
Drip Leg
HWS
Gas Line
Pressure Relief Valve
(Drain Line not
shown for clarity)
Water Shutoff Valve
Gas
Shutoff Valve
Water
Shutoff
Valve
Check Valve
Return Line
NOTE: Condensate Drain not shown for clarity.
Expansion
Tan k
Typical Installation
Dedicated Return Line
Water
Shutoff
Valve
Water
Shutoff
Valve
Water Shutoff Valve
WATER HEATER BASICS
TYPICAL INSTALLATIONS (X3® Model Shown)
6 • Residen al Gas Tankless Water Heater Use and Care Guide
WATER HEATER BASICS
DIMENSIONS
16.54 in
42.00 cm
5.09 in
12.92 cm
6.70 in
17.00 cm
4.00 in
10.16 cm
C
L
12.28 in
31.20 cm
33.80 in
85.88 cm
3.73 in
9.47 cm
Wall
Water heater wall
mount contact point.
16.12 in
40.96 cm
8.31in
21.12 cm
5.08 in
12.90 cm
3.22 in
8.22 cm
6.58 in
16.72 cm
Wall Studs
Dry Wall
41.78 in
106.13 cm
26.70 in
67.82 cm
Residen al Gas Tankless Water Heater Use and Care Guide • 7
WATER HEATER BASICS
Table 1: Supply Connec ons
Item DESCRIPTION MEASUREMENT CONNECTION SIZE
1 HOT OUTLET 9.00 in/22.86 cm 3/4 in MNPT
2 GAS INLET 6.90 in/17.52 cm 1/2 in MNPT
3 CONDENSATE 3.20 in/8.07 cm 1/2 in MNPT
4 COLD INLET 4.80 in/12.20 cm 3/4 in MNPT
WALL
1
2
3
4
SUPPLY CONNECTIONS
8 • Residen al Gas Tankless Water Heater Use and Care Guide
X3® Models: Come with the X3® Scale Preven on Technology cartridge and pressure relief valve.
M Models: Come with the Bypass cartridge installed.
All other specifi ca ons are the same.
Table 2: Specifi ca ons
Model THR-160 THR-180 THR-199
Natural Gas/Propane Input
(Minimum Operating Range)
BTU/h 9,000
Natural Gas/Propane Input
(Maximum Operating Range)
BTU/h 160,000 180,000
199,000
Gas Connection 1/2 in MNPT
Water Connections 3/4 in NPT
Water Pressure* psi (MPa) 15 - 150 (0.1 - 1)
Water Flow Rate gpm (Lpm) 0.26 - 10.5 (1.0 - 39.7), Activation min: 0.4 (1.5)
Natural gas
Inlet Pressure
in W.C. (kPa)
Min 3.5 (0.87)
Max. 10.5 (2.62)
Propane
Inlet Pressure
in W.C. (kPa)
Min 8.0 (1.99)
Max. 13.0 (3.24)
Weight lbs (kg) 104 (47.2)
Dimensions
(including X3®)
inch W 16.54 x H 41.78 x D 16.12
cm W 42.00 x H 106.13 x D 40.96
Ignition Electronic Ignition
Electric
Supply 120 V, 60 Hz, <5 A
Water Heater Category** Category IV
Maximum Pipe length
(Hot Water supply line plus the Dedicated
Return line.) See Table 13 for addi onal
informa on.
Pipe
Diameter
3/4 in 500 ft (152.4 m)
1/2 in 200 ft (61 m)
*40 psi or above is recommended for maximum flow.
**Water Heater Category - Does not apply to Outdoor or Direct Vent Installations.
Category IV - a water heater that operates with a positive vent static pressure and with a vent gas temperature that may cause excessive
condensate production in the vent.
NOTE:
• Check the rating plate to ensure that 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
obligation.
WATER HEATER BASICS
SPECIFICATIONS
Residen al Gas Tankless Water Heater Use and Care Guide • 9
IMPORTANT SAFETY INFORMATION
Read and follow all safety messages and instruc ons in this
manual.
This is the safety alert symbol. It is used to alert you to
poten al physical injury hazards. Obey all safety messages that
follow this symbol to avoid possible property damage, serious
injury or death. Do not remove any permanent instruc ons, labels,
or the data plate from either the outside of the water heater or on
the inside of the access panels. Keep this manual near the water heater.
WARNING! If the informa on in these instruc ons is not followed exactly, a fi re
or explosion may result causing property damage, personal injury or death. Do not
store or use gasoline or other fl ammable vapors and liquids in the vicinity of this or
any other appliance.
An odorant is added by the gas supplier to the gas used by this water heater. This
odorant may fade over an extended period of me. Do not depend upon this odorant
as an indica on of leaking gas. We recommend installing a fuel gas and carbon
monoxide detector.
This product is cer fi ed to comply with a maximum weighted average of 0.25% lead
content.
DANGER indicates a hazardous
situa on that, if not avoided, will
result in death or serious injury.
WARNING indicates a hazardous
situa on that, if not avoided, could
result in death or serious injury.
CAUTION indicates a hazardous
situa on that, if not avoided, could
result in minor or moderate injury.
NOTICE indicates prac ces not related
to physical injury.
DANGER
WARNING
CAUTION
NOTICE
*Operate the Pressure Relief Valve annually
and inspect Pressure Relief Valve every 2-4
years (see the label on the Pressure Relief
Valve for maintenance schedule). If no label
is attached to the Pressure Relief Valve,
follow the instructions in the Maintenance
section of this manual.
See the Regular Maintenance section for
more information about maintaining this
water heater.
Important informa on to keep
Fill out this sec on and keep this manual in
the pocket of the water heater for reference.
Date Purchased:
Model Number:
Serial number:
Maintenance performed:* Date:
10 • Residen al Gas Tankless Water Heater Use and Care Guide
To reduce the risk of property damage,
serious injury or death, read and follow
the precau ons below, all labels on the
water heater, and the safety messages and
instruc ons throughout this manual.
RISKS DURING
INSTALLATION AND
MAINTENANCE
Li ing Risk
WARNING! The
water heater is
heavy. Follow these
precau ons to reduce the risk of property
damage, injuries from li ing or impact
injuries from dropping the water heater.
• Use at least two people to li the water
heater.
• Be sure you both have a good grip
before li ing.
• Use an appliance dolly or hand truck to
move the water heater.
Explosion Risk
WARNING! Read the
water heater’s data plate
to determine the type of gas required.
Failure to follow these instruc ons can
result in serious injury or death from
explosion, fi re or carbon monoxide
poisoning.
• Do not connect a natural gas water
heater to an L.P. gas supply.
• Do not connect an L.P. gas water heater
to a natural gas supply.
• Use a new gas supply line approved for
Propane or Natural Gas that meets all
local and state/provincial codes.
• Install a full port shut-off valve on the
gas supply line.
• Maintain the Pressure Relief Valve
properly. Follow the maintenance
instruc ons provided by the
manufacturer of the Pressure Relief
Valve (label a ached to Pressure
Relief Valve). If no label is a ached to
the Pressure Relief Valve, follow the
instruc ons in the Regular Maintenance
sec on of this manual. An explosion
could occur if the Pressure Relief Valve
or discharge pipe is blocked. Do not
cap or plug the Pressure Relief Valve or
discharge pipe.
Gas Pressure
WARNING! The gas supply pressure
must not exceed the maximum supply
pressure as stated on the water
heater’s ra ng plate. Have a qualifi ed
person (licensed plumber, gas company
personnel, or authorized service
technician) check for proper gas pressure.
Gas pressures exceeding the maximum
supply pressure as stated on the water
heater’s ra ng plate can result in serious
injury or death from explosion or fi re.
RISKS DURING
OPERATION
Scalding Risk
This water heater
can make water hot
enough to cause
severe burns instantly, resul ng in severe
injury or death.
• Feel water before bathing or showering.
• To reduce the risk of scalding, install
Thermosta c Mixing Valves (tempera-
ture limi ng valves) at each point-of-
use. These valves automa cally mix hot
and cold water to limit the temperature
at the tap. Mixing valves are available at
your local plumbing supplier. Follow the
manufacturer’s instruc ons for installa-
on and adjustment of the valves.
• Water temperatures over 125°F (52°C)
can cause severe burns instantly or death
from scalding. The water temperature
is set at 120°F (50°C) from the factory
to minimize any scalding risk. Before
bathing or showering, always check the
water temperature. Higher temperatures
increase the risk of scalding, but even at
120°F, hot water can scald. If you choose
a higher temperature se ng, Thermo-
sta c Mixing Valves located at each point-
of-use are par cularly important to help
avoid scalding.
Table 3: Burn/Scald Table
Temperature Time to Produce a
Serious Burn
120°F (49°C) More than 5 minutes
125°F (52°C) 1½ to 2 minutes
130°F (54°C) About 30 seconds
135°F (57°C) About 10 seconds
140°F (60°C) Less than 5 seconds
145°F (63°C) Less than 3 seconds
150°F (66°C) About 1½ seconds
155°F (68°C) About 1 second
For more informa on about changing the
factory temperature se ng, refer to the
“Adjus ng the Temperature” sec on in
this manual.
• Water temperature will be ho er if
someone adjusted the set temperature
to a higher se ng.
• Should overhea ng occur or the burner
fail to shut off , turn off the manual gas
supply valve to the water heater and call
a qualifi ed person.
IMPORTANT SAFETY INFORMATION
Residen al Gas Tankless Water Heater Use and Care Guide • 11
IMPORTANT SAFETY INFORMATION
To reduce the risk of unusually hot water
reaching the fi xtures in the house, install
Thermosta c Mixing Valves at each point-
of-use.
If anyone in your home is at par cular
risk of scalding (for example, the elderly,
children, or people with disabili es) or if
there is a local code or state/provincial law
requiring a certain water temperature at
the hot water tap, these precau ons are
par cularly important.
According to a na onal standard American
Society of Sanitary Engineering (ASSE
1070) and most local plumbing codes, the
water heater’s thermostat should not be
used as the sole means to regulate water
temperature and avoid scalds.
Water Contamina on Risk
Do not use chemicals that could
contaminate the potable water supply. Do
not use piping that has been treated with
chromates, boiler seal, or other chemicals.
Suitable for potable water hea ng only.
Fire Risk
To reduce the risk of a
fi re that could result in
property damage, or
serious injury or death:
• Do not store things that can burn easily
such as paper or clothes next to the
water heater.
• Do not store or use gasoline or other
fl ammable substances in the vicinity of
this or any other appliance.
• Do not use this appliance if any part has
been in contact with or been immersed
in water. Immediately call a qualifi ed
installer or service agency to replace a
fl ooded water heater. Do not a empt to
repair the unit. It must be replaced.
Explosion Risk
High pressures in the
water heater can cause
an explosion resul ng in
property damage, serious injury or death.
A Pressure Relief Valve is required to be
installed on the water heater. A Pressure
Relief Valve is supplied with X3® models
and shall be fi eld supplied for M models.
Addi onal pressure protec ve equipment
may be required by local codes.
A na onally recognized tes ng laboratory
maintains public inspec on of the valve
produc on process and cer fi es that it
meets the requirements for Relief Valves
for Hot Water Supply Systems, ANSI
Z21.22. The Pressure Relief Valve’s relief
pressure must not exceed the working
pressure ra ng of the water heater as
stated on the ra ng plate.
Carbon Monoxide Risk
WARNING! This
water heater operates
by burning gas. Carbon
monoxide is a
colorless, odorless, gas
that is a by-product of
burning of fuels such as
coal, wood, charcoal, oil, kerosene,
propane, and natural gas. Breathing
excessive and abnormal amounts of
carbon monoxide can cause carbon
monoxide poisoning, resul ng in serious
injury or death. This water heater must
be supplied with adequate combus on
air and must be properly vented to the
outdoors. Have a qualifi ed person
(licensed plumber, authorized gas
company personnel, or authorized service
technician) install the ven ng system
using these installa on instruc ons.
Install a fuel gas and carbon monoxide
detector in the living areas of your home.
• Failure to follow these instruc ons can
result in serious injury or death from
carbon monoxide poisoning.
12 • Residen al Gas Tankless Water Heater Use and Care Guide
Read Before
Installa on
1
Review all of the instruc ons
before you begin work. Improper
installa on can damage the
water heater, your home and other
property, and can present risks of serious
injury or death.
2
This water heater is designed as
a Category IV, posi ve vented
sta c pressure water heater
(vent gas temperatures may cause
excessive condensate produc on in the
vent,) which takes its combus on air
either from the installa on area or from
air ducted to the unit from the outside.
This water heater must be installed:
• Following all local codes, or in the ab-
sence of local codes, follow the current
edi on of ANSI Z223.1/NFPA 54, Na on-
al Fuel Gas Code in the USA or B149.1,
Natural gas and propane installa on
code in Canada.
• For installa on in manufactured homes
(mobile homes) follow the current
edi on of The Manufactured Home
Construc on and Safety Standard, Title
24 CFR, Part 3280 and/or CSA Z240 MH
Series, Manufactured Homes.
• Follow the electrical code requirements
of the local authority having jurisdic-
on. In the absence of such require-
ments, follow the current edi on of the
Na onal Electrical Code ANSI/NFPA 70
in the U.S. or the current edi on of CSA
C22.1 Canadian Electrical Code Part 1 in
Canada.
These are available from the following:
CSA Group, Inc.
United States:
8501 East Pleasant Valley Road
Cleveland, OH 44131
Canada:
178 Rexdale Blvd.
Toronto, ON
Canada M9W 1R3
Na onal Fire Protec on Associa on
1 Ba erymarch Park
Quincy, MA 02269
Check with local code offi cials about codes
governing this installa on. Have your
installa on inspected by a code offi cial
to ensure the installa on meets all local
codes.
NOTICE: Installa on and service must
be performed by a qualifi ed installer (for
example, a licensed plumber or gas fi er).
Otherwise, the warranty will be void.
The installer (licensed professional) is
responsible for the correct installa on of
the water heater and for compliance with
all na onal, state/provincial, and local
codes.
Massachuse s code requires this water
heater to be installed in accordance with
Massachuse s
248-CMR 2.00 and 248-CMR 5.00: State
Plumbing Code. Other local and state/
provincial authori es may have similar
requirements or other codes applicable to
the installa on of this water heater.
3
Before you start, check the
following:
Warning! Do not store or use
fl ammable materials, vapors, or liquids
in the same loca on where this water
heater is installed.
• All gas water heaters require correct
installa on to ensure safe and effi cient
opera on. This manual must be
followed exactly. Read the en re manual
before installa on and review the Safety
Guidelines” Sec on.
• Carefully plan the installa on loca on of
the heater and vent termina ons.
• The water heater must be installed
where the proper amount of combus-
on air will be available to it at all mes
without obstruc ons. When installed
indoors, the water heater can be direct
vented.
• The length of piping between the water
heater and fi xture determines the me
it takes for the hot water to arrive. Con-
sider installing the water heater closer
to the fi xtures, if the plumbing system
allows for it. The water heater should be
the fi rst appliance to access the water
line a er u li es water meter.
• Locate your water heater close to a
drain where water leakage will not do
damage to surrounding areas. As with
any water hea ng appliance, the poten-
al for leakage at some me in the life
of the product does exist. A drain pan,
or other means of protec on against
water damage, is recommended to be
installed under the water heater in case
of leaks to lessen the chance of sustain-
ing property damage. In addi on, you
may install an ac ve water leak detector
with a shutoff valve which can turn off
the water supply in the event of a leak.
The manufacturer is not responsible for
damage due to water leaks.
• The water heater shall be securely
wall-mounted or mounted on a stand.
• Maintain proper space for servicing.
Install the unit so that it can be con-
nected or removed easily. Refer to the
"Unit clearances" sec on page 17 for
proper clearances.
• For outdoor installa ons, locate the
water heater in an open , unroofed
area. Maintain 3 in. (76 mm) minimum
clearance from the le and right sides of
the unit.
• The manufacturer does not recommend
installing the water heater in an a
c
due to safety issues. See the installation
section for further information.
• Failure to observe these warnings could
result in severe personal injury, death,
and/or property damage.
GETTING STARTED
Residen al Gas Tankless Water Heater Use and Care Guide • 13
GETTING STARTED
Ven ng/Combus on:
• Do not install the heater where water,
debris or fl ammable vapors may get into
the fl ue terminal. This may cause damage
to the heater and void the warranty.
• Do not locate your heater in a pit or loca-
on where gas and water can accumulate.
• Do not install the exhaust vent for indoor
and outdoor models within
3 (914 mm) of an overhang.
• Do not install the unit where the exhaust
vent is poin ng into any opening in a
building or where the noise may disturb
your neighbors. Make sure the vent
termina on meets the required clearance
from any doorway or opening to prevent
exhaust from entering a building. Check
local code requirements prior to installa-
on.
• Vent termina on must be at least 2
(610 mm) away from both the inside and
outside corners for outdoor installa on
and direct-vent installa on.
Outside
Corner
ϯŌ
min.
ϮŌ
min.
Overhang
ϮŌ
min.
Inside
Corner
Figure 1 - Sidewall clearances
• Do not install next to a dryer or any
source of airborne debris that can be
trapped inside the combus on chamber,
unless the system is direct-vented. When
direct vented, do not install the air intake
near the dryer vent or any source of
airborne debris.
• Do not common vent this water
heater with any other water heaters or
appliances.
h^ϭŌ;ϯϬĐŵͿŵŝŶ
ĂŶĂĚĂϯŌ;ϵϭĐŵͿŵŝŶ
h^ϭŌ;ϯϬĐŵͿŵŝŶ
ĂŶĂĚĂϯŌ;ϵϭĐŵͿŵŝŶ
h^ϭŌ;ϯϬĐŵͿŵŝŶ
ĂŶĂĚĂϯŌ;ϵϭĐŵͿŵŝŶ
h^ϭŌ;ϯϬĐŵͿĂďŽǀĞŐƌĂĚĞĂŶĚ
ĂďŽǀĞĂŶƟĐŝƉĂƚĞĚƐŶŽǁůĞǀĞů
ĂŶĂĚĂϭŌ;ϯϬĐŵͿĂďŽǀĞŐƌĂĚĞ
ŶƟĐŝƉĂƚĞĚƐŶŽǁůĞǀĞů
Figure 2 - Minimum Vent Clearances (Indoor)
h^ϰŌ;ϭϮϮĐŵͿŵŝŶ
h^ϰŌ;ϭϮϮĐŵͿŵŝŶ h^ϰŌ;ϭϮϮĐŵͿŵŝŶ
Figure 3 - Minimum Vent Clearances (Outdoor Ven ng)
14 • Residen al Gas Tankless Water Heater Use and Care Guide
GETTING STARTED
4
Before you start, be sure you
have the following tools and
supplies:
• Plumbing tools and supplies appropri-
ate for the type of water pipes in your
home.
• Thread sealant tape or pipe joint com-
pound approved for potable water.
• Pipe dope approved for gas connec ons
or gas tape.
• For homes with water lines using thread-
ed connectors suitable for the specifi c
type of plas c pipe used: CPVC or PEX
(cross-linked polyethylene). Do not use
PVC pipe.
• Non-corrosive gas leak detec on
solu on made from hand dishwashing
soap mixed with water (1 part soap
to 15 parts water) or children’s soap
bubbles and a small, so -bristled brush
or approved gas leak detec on device.
• An appliance dolly or hand truck to
move the water heater.
Recommended Accessories
• Automa c water leak detec on and
shut-off device
• Thermosta c Mixing Valves at each
point-of-use
• Fuel gas and carbon monoxide detector
Included Items
Table 4: Items Included with your Water Heater
Item Descrip on
Manual Installa on Instruc ons and Use & Care Guide.
Pressure Relief
Valve
Pressure Relief Valve rated up to 150 psi and the maximum Btu/hr of the water
heater.
(Included with X3® models; Field supplied for M models)
Wall Moun ng
Bracket
Kit for moun ng water heater contains:
• Moun ng Bracket (1x)
• 1/4 in x 3 in Lag Bolts (4x)
Screws for
Vent Ports
Screws to secure the vent piping to the vent ports. See “Installing the Vent Pipe” on
page 23.
• 3/16 in x 3/8 in Vent Screw (x2)
X3® or Bypass
Cartridge Screws
(x1)
(x2)
Screws to secure the X3® Cartridge
• M4-12 mm (1x)
• M4-25 mm (2x)
Cascading Cable
Cascading Cable for electronically connec ng tankless water heaters in series for
greater output.
• P/N 100377343
Fuel Conversion Kit
Convert heater from Natural Gas (NG) to Liquid Propane (LP). Kit contains:
• LP Diaphragm
• Gas Conversion Label (1x)
• Gas Conversion Instruc on (1x)
• Plas c Retainer (1x)
2 in Bird Screens
Bird screen to restrict small animals, birds, pests, and other foreign objects from
entering the vent system. Kit contains 2 screens sized for 2 in vent elbows.
Residen al Gas Water Heater Use and Care Guide • 15
Available Accessories
Table 5: Accessories available for your Water Heater
Item Descrip on
X3® Cartridge
Add to an M model heater to prevent scale buildup and eliminate the need for
annual descaling maintenance.
• P/N 100368986
Wi-Fi Module Kit
Wi-Fi Module for electronically connec ng tankless water heaters to the Internet
and adapter to connect to the water heater.
• P/N 100371922
Remote
Temperature
Controller
Remote Temperature Controller with 10 (3 m) cable.
• P/N 100377310
Communica on
Cables
Communica on Cable Extensions for Remote Temperature Controller, Wi-Fi Mod-
ule, or Remote Recircula on Kit.
• P/N 100377341 for 10 (3 m)
• P/N 100377342 for 32 (10 m)
Remote
Recircula on Kit
Remote Recircula on Kit engages heater and recircula on at the touch of the
bu on for on-demand hot water. Kit contains:
• P/N 100371920 for One Receiver and Two Bu on Kit
• P/N 100371921 for One Receiver and Three Bu on Kit (Not Pictured)
Individual Spare
Bu ons
Add more Remote Recircula on Bu ons to a system as needed. Add up to
a maximum of 30 bu ons.
• P/N 100377309
Cartridge Freeze
Protec on
Cartridge Freeze Protec on can add an extra layer of freeze protec on to external
cartridge.
• P/N 100325654 for X3® Models
• P/N 100371918 for Bypass Models
Pipe Cover
Pipe Cover protects plumbing connec ons to the heater while improving the
appearance of the installa on. Affi xes to bo om of heater.
• P/N 100374697
GETTING STARTED
16 • Residen al Gas Water Heater Use and Care Guide
Item Descrip on
Neutralizer Assembly
Kit
Neutralizer Assembly neutralizes the condensate (acidic water) that forms in the
heat exchanger of the water heater. It connects to the condensate drain port of the
water heater by using connectors included with the neutralizer kit.
• P/N 100112159
Outdoor Vent Cap
Kit
Outdoor Installa on Kit containing the outdoor vent cap and User Interface Cover
• P/N 100369060
Crossover Valve Kit
Crossover Valve for recircula on systems without a dedicated return line.
The kit includes a lead free Stainless/Brass Crossover Valve, Brass Tees and
2 . Flex Hose.
• P/N 100327167
Isola on Valve Kit
with Pressure Relief
Valve
Isola on Valve supports rou ne maintenance and allows for draining and fl ushing
the heater; whereas, the Pressure Relief Valve, as the name implies, serves to limit
internal pressure in the system.
• P/N 100112156
GETTING STARTED
Residen al Gas Tankless Water Heater Use and Care Guide • 17
Installa on Environment
Proper moun ng and clearance
The water heater shall be securely
mounted on a wall that can support
the weight of the water heater. A wall
moun ng bracket is supplied with the
water heater to securely mount the
water heater to wall studs. The water
lines, gas line, condensate drain line, and
pressure relief valve discharge line shall
be supported using fi eld supplied pipe
hangers. The water heater shall not bear
the weight of these lines. The water heater
requires proper installa on clearance for
opera on and service as described in Unit
Clearances sec on.
Warning! The installer (licensed
professional) is responsible for the correct
installa on of the water heater and
for compliance with all na onal, state/
provincial, and local codes.
Atmosphere temperature
Install the water heater in a heated area
where below freezing temperatures
cannot occur. A pipe cover is
recommended when the water heater
is installed outdoors because it provides
be er protec on from the elements. The
warranty will not be covered if the water
heater is damaged due to freezing. See
”Freeze Protec on System” on page 57.
Combus on air supply
The water heater requires fresh
combus on air and should be free of
corrosive elements and fl ammable vapors.
If it is installed in a contaminated area
or in a confi ned area, direct ven ng
installa on is recommended.
Proper ven la on
For proper opera on the water heater
must be vented in accordance with the
sec on “Ven ng” of the current edi on
of the ANSI Z223.1/NFPA 54, Na onal
Fuel Gas Code in the United States and/or
Sec on 8 of the B149.1, Natural gas and
propane installa on code in Canada, as
well as applicable local building codes.
Condensate Drain line
The condensate produced is acidic. Drain
the condensate in accordance with all
local codes and common safety prac ces.
Unit Clearances
Warning! Maintain all clearances
around the water heater. Failure to do
so could create a fi re hazard, poten ally
leading to death, serious injury, and/or
property damage.
Indoor
Top:
12 in (305 mm)
Side:
3 in (76 mm)
Front:
4 in (102 mm)
Bottom:
18 in (458 mm)
Back:
0.5 in (13 mm
)
Side:
3 in (76 mm)
Figure 4 - Indoor Clearances
Top:
12 in (305 mm)
Side:
3 in (76 mm)
Front:
4 in (102 mm)
Bottom:
18 in (458 mm)
Back:
0.5 in (13 mm)
Side:
3 in (76 mm)
Overhang:
36 in (914 mm)
Figure 5 - Outdoor Clearances
It is recommended that the front should
have 24 inches (610 mm) of clearance for
maintenance.
Moun ng the Water
Heater
1. Secure the wall moun ng bracket
with the four supplied lag bolts to
the wall studs. See Figure 6. DO NOT
secure to the drywall only. NOTICE:
The supplied fasteners are for wood
studs only. When moun ng on any
other surface use fasteners approved
for that wall material/construc on.
Make sure to level the bracket.
16” (406.4 mm) Center
New Construction Configuration Shown:
Drywall cut away to show horizontal bracing.
Wall Stud
Wall Stud
Horizontal Blocking - Top
Horizontal Blocking - Bottom
Screws
Figure 6 - Wall bracket installa on.
1. Hang the water heater on the wall
bracket. See Figure 7.
Wall
Bracket
Figure 7 - Moun ng the water heater.
2. Secure the water heater fi rmly
fastening appropriate screws into the
upper bracket/bo om brackets of the
water heater and wall. NOTICE: these
screws are not provided.
Securewithscrews.
Securewithscrews.
Figure 8 - Use moun ng screws.
INSTALLATION
18 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
Combus on Air and
Ven ng Installa on
Combus on Air
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. This sec on does not apply if
the water heater is direct vented. Consult
a qualifi ed person if you’re unsure of the
proper way to supply air to your water
heater.
WARNING! This gas water heater
requires an adequate source of clean air
for combus on and ven la on. Without
suffi cient air, your water heater will have
frequent outages and may emit excessive
and abnormal amounts of carbon
monoxide.
Before beginning:
Calculate total Btu/hr ra ng of all
appliances.
To calculate the combus on air and
ven la on required, add up the total Btu/
hr ra ngs of all gas burning appliances
(e.g., water heaters, furnaces, clothes
dryers) in the same area.
Your water heater’s Btu/hr ra ng is on
the ra ng plate, located on the side of the
water heater. The Btu/hr ra ngs should
be on the other appliances’ data plates.
If you have trouble determining the Btu/
hr ra ngs, contact the manufacturer or
have a qualifi ed person determine the
ven la on requirements.
NOTICE: If you are replacing your old
water heater with one that has a higher
Btu/hr ra ng, the amount of ven la on
required may be greater.
Example:
Gas Burning Appliance Btu/hr Ra ng
Gas Water Heater 199,000
Furnace 75,000
Dryer 20,000
Total 294,000
Your Appliances:
Gas Burning Appliance Btu/hr Ra ng
Gas Water Heater
Tota l
Op on A: Installa on without
outside ven la on (not
recommended)
Ven la on with outdoor 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 installa on loca on
has enough ven la on, contact your local
gas u lity company or code offi cials for a
safety inspec on.
The following instruc ons will help
determine if it may be possible to install
without outside ven la on. If there is
not enough ven la on, you will need to
ven late with outside air.
Check for Chemicals:
Installa ons where corrosive chemicals
may be present require outside air. Air
for combus on and ven la on must be
clean and free of corrosive or acid-forming
chemicals such as sulfur, fl uorine, 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.
A1: Calculate the air volume of
the room
Air requirements depend on the size of
the room.
Floor Area (square feet) x Ceiling Height
(feet) = Room Volume (cubic feet)
If there are large objects in the room (e.g.,
refrigerator, furnace, car), subtract their
volume from the volume of the room to
get a be er es mate of the air available.
Room Volume – Object Volume = Air
Volume
A2: Calculate required air
volume
A water heater installed in an unconfi ned
space, such as an a c or garage, requires
that the space be at least 50 cubic feet per
1,000 Btu/hr of the total input for all gas
burning appliances in the same area.
[Total Btu/hr/1000] x 50 = Cubic feet of air
required.
Residen al Gas Tankless Water Heater Use and Care Guide • 19
INSTALLATION
Example:
(294,000 / 1000) x 50 = 14,700
If the air volume of the room is less than
the required air volume, you must provide
two permanent outside air openings that
draw in suffi cient air. Use Op on B.
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.
A3: Check that combus on
ven la on is adequate
Because modern homes are o en well-
sealed to prevent dra s, a large room
may not provide enough combus on air
without ven la on. Confi rm that your
installa on has enough combus on air.
Op on B: Installa on with
outside ven la on
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 typically requires
two openings. One opening must be
within 12 inches from the fl 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 according to Table 6. Two
openings must be used when ven la ng
with air from another room.
B1: Determine type of
ven la on
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 confi ned spaces
smaller than 50 cubic feet per 1,000
Btu/hr as calculated in sec on A or
when ge ng air from another room.
5. From a larger room inside the house
(not recommended — refer to sec on
A to determine if the combined vol-
ume of the room may be adequate)
B2: Determine minimum free
area required for each vent
opening
The size of the vent openings depends on
the total Btu/hr ra ng of all appliances
in the space (use your calcula on from
“Before Beginning”) and the type of vent
used. Table 6 provides the minimum free
area for each vent opening depending on
the type of ven la on.
B3: 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 grille itself blocks
some of the free area, so the opening 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% = .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 ÷ .75 = 134 sq in).
If you do not know the % (percentage)
free area for your louver or grille, use the
following values:
• For wood louvers or grilles: 20%
• For metal louvers or grilles: 60%
Follow these rules to ensure that vents
and ducts provide adequate air fl ow:
• Each vent opening must be no smaller
than 100 square inches.
• Ducts must have the same cross-sec on-
al 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 in or
larger.
• Movable louvers must be locked open
or interconnected with the equipment
so that they open automa cally during
opera on.
• Keep louvers and grilles clean and free
of debris or other obstruc ons.
B4: 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 fl ammable
chemicals. A failure due to corrosive
chemicals in the air is not covered by the
warranty. Combus on air must be free
of acid-forming chemicals such as sulfur,
fl uorine, and chlorine. Be sure that air at
the vent inlets is free of such chemicals.
B5: Check that combus on
ven la on is adequate
To confi rm that your installa on has
enough combus on air.
20 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
Combus on Air Supply Op ons
Gable vent
to outdoors
Install above
ŝŶƐƵůĂƟŽŶ
Outlet air to
ĂƫĐϭŝŶ
2
;ϲϱĐŵ
2
)
per 4,000 Btu/hr
/ŶůĞƚĂŝƌĨƌŽŵ
ƚŚĞĐƌĂǁůƐƉĂĐĞ
KƉĞŶ ĨŽƵŶĚĂƟŽŶ ǀĞŶƚ
ŽŶĮŶĞĚ
^ƉĂĐĞ
Alternate
Air Inlet
ϭŝŶ
2
;ϲϱĐŵ
2
)
per 4 000 Btu/hr
Figure 9 - Direct to Outdoors Openings
Two permanent
Openings
1 in
2
(6.5 cm
2
)
per 4,000 Btu/hr
12 in (305 mm)
maximum
12 in (305 mm)
maximum
ŽŶĮŶĞĚ
Space
Figure 10 - Direct to outdoors openings. Two
permanent openings.
Outlet air to
ĂƫĐϭŝŶ
2
;ϲϱĐŵ
2
)
per 4,000 Btu/hr
/ŶůĞƚĂŝƌĚƵĐƚ
ϭŝŶ
2
;ϲϱĐŵ
2
)
per 4,000 Btu/hr
ŽŶĮŶĞĚ
^ƉĂĐĞ
ϭϮŝŶ;ϯϬϱŵŵͿ
ŵĂdžŝŵƵŵ
'ĂďůĞǀĞŶƚ
ƚŽŽƵƚĚŽŽƌƐ
/ŶƐƚĂůůĂďŽǀĞ
ŝŶƐƵůĂƟŽŶ
Figure 11 - Ver cal Duct Openings
1 in
2
(6.5 cm
2
)
per 2,000 Btu/hr
ŽŶĮŶĞĚ
Space
Outlet
Inlet
KƵƚĚŽŽƌ
Air Ducts
1 in
2
(6.5 cm
2
)
per 2,000 Btu/hr
Figure 12 - Horizontal Duct Openings
ŽŶĮŶĞĚ
^ƉĂĐĞ
1 in
2
(6.5 cm
2
)
ƉĞƌϯϬϬϬBtuŚƌ
ůƚĞƌŶĂƟǀĞ
KƉĞŶŝŶŐ
>ŽĐĂƟŽŶ
Figure 13 - Single Opening
Two permanent
Openings
1 in
2
(6.5 cm
2
)per
1,000 Btu/hr
12 in (305 mm)
maximum
12 in (305 mm)
maximum
ŽŶĮŶĞĚ
Space
Figure 14 - Two permanent openings
Table 6:
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/hr input ra ng for all gas burning appliances within a confi ned space.
Opening Source Minimum Free Area
Direct to outdoors* 1 in
2
(6.5 cm
2
) per 4,000 Btu/hr (See Figure 9 & Figure 10)
Ver cal ducts 1 in
2
(6.5 cm
2
) per 4,000 Btu/hr (see Figure 11)
Horizontal ducts 1 in
2
(6.5 cm
2
) per 2,000 Btu/hr (see Figure 12)
Single Opening 1 in
2
(6.5 cm
2
) per 3,000 Btu/hr (see Figure 13)
Two permanent openings
to another room**
1 in
2
(6.5 cm
2
) per 1,000 Btu/hr (see Figure 14)
Opening: 100 in
2
(645 cm
2
) Min
Minimum dimension of air openings: no less than 3 in (76 mm)
*These openings connect directly with the outdoors through a ven lated a c, a ven lated crawl space, or through an outside wall.
**United States: For direc on on combining spaces in diff erent stories within the structure, refer to the current edi on of the Na onal Fuel Gas Code ANSI
Z223.1/NFPA 54. In Canada, refer to the current edi on of B149.1 Natural gas and propane installa on code.
Residen al Gas Tankless Water Heater Use and Care Guide • 21
INSTALLATION
Ven ng
WARNING! Carbon Monoxide Hazard.
This water heater must be supplied with
adequate air and vented to outdoors.
The vent system must be installed
by a qualifi ed person. Examples of a
qualifi ed person include gas technicians,
authorized gas company personnel, and
authorized service technicians. Failure to
properly vent the water heater can result
in severe injury or death from carbon
monoxide poisoning.
The Indoor model must be vented in
accordance with the current edi on of
ANSI Z223.1/NFPA 54, Na onal Fuel Gas
Code in the USA or B149.1, Natural gas
and propane installa on code in Canada,
as well as applicable local building codes.
The use of ven ng materials approved for
Category III/IV appliances is recommended
whenever possible. However, the Indoor
model may also be vented with plas c
pipe materials such as ABS, PVC (solid
core), CPVC (solid core), or polypropylene.
For details, please refer to the Exhaust
Vent (ABS, PVC, CPVC, or Polypropylene
Vent) Sec on on page 23. Vent
installa ons in Canada which u lize plas c
vent systems must use ven ng that is
cer fi ed to ULC S636.
Ven ng may not intermingle with other
manufactured material types, other than
approved adapters.
General rules for ven ng water heaters:
• Follow the vent pipe manufacturer’s
installa on instruc ons when installing
the vent pipe.
• Place the water heater as close as possi-
ble to the vent termina on.
• The vent collar of the water heater must
be fastened directly to an unobstructed
vent pipe.
• Do not weld, glue, or permanently bond
the vent pipe to the water heater’s vent
collar.
• Do not cut or alter the vent collar of the
unit.
• The vent must be easily removable from
the top of the water heater for normal
service and inspec on of the unit.
• The water heater vent must not be com-
mon vented to any other gas appliance
or vent stack.
• Air supply pipe can be made of ABS, PVC
(solid core), CPVC (solid core), polypro-
pylene, or Category lll/IV stainless steel.
• Use of cellular core PVC (ASTM F891),
cellular core CPVC, or Radel® (poly-
phenylsulfone) in nonmetallic ven ng
systems is prohibited
• Covering non-metallic vent pipe and
fi ngs with thermal insula on is pro-
hibited.
• Sidewall ven ng is recommended for
the Indoor model. Ver cal ven ng (roof
termina on) is acceptable.
• The manufacturer recommends running
the exhaust vent and the intake pipe as
parallel as possible.
• For roo op ven ng, a rain cap or other
form of termina on that prevents rain
water from entering into the water heat-
er must be installed.
• 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 approved vent pipe.
• The water heater shall not be connected
to a chimney fl ue serving a separate
appliance, designed to burn solid fuel.
General rules for vent termina ons:
• Avoid loca ng the water heater vent
termina on near any air intake devices.
These fans can pick up the exhaust fl ue
products from the water heater and
return them to the building. This can
create a health hazard.
• Locate the vent termina on so that it
cannot be blocked by any debris, at any
me. Most codes require that the termi-
na on be at least 12 in
(305 mm) above grade and an cipated
snow level, but the installer may deter-
mine if it should be higher depending
on the job site condi on and applicable
codes.
• A proper sidewall termina on is rec-
ommended when the water heater is
vented through a sidewall.
• Check the clearances from the exhaust
termina on to the air inlet or opening.
• To reduce the risk of carbon monoxide
poisoning, install a fuel gas and carbon
monoxide detector. Install and maintain
the detector in accordance with the
manufacturer’s instruc ons and local
codes.
Replacing a Water Heater
Using the Exis ng Vent System
WARNING! Improper ven ng of this
appliance can result in excessive levels
of carbon monoxide which can result
in severe personal injury or death.
Improper installa on can cause nausea
or asphyxia on, severe injury or death
from carbon monoxide and fl ue gases
poisoning. Improper installa on will void
product warranty.
Do not use Category I or Category II
ven ng systems with this water heater.
If exis ng ven ng and vent termina ons
are used, they MUST be cleared of ALL
restric ons for proper opera on, such as a
restricter plate.
Read the “Installing Vent Pipe” sec on
of this manual and make sure your vent
system is properly installed. Inspect the
exis ng vent system for obstruc ons,
corrosion, and proper installa on. Repair
or replace if necessary.
22 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
Table 7: Plas c Vent Pipe Table
Item Material United States Canada
Exhaust pipe and
Fi ngs
Schedule 40 PVC ANSI/ASTM D1785
ULC S636 Cer fi ed
Materials Only
PVC-DWV ANSI/ASTM D2665
Schedule 40 CPVC ANSI/ASTM F441
Schedule 40 ABS-DWV ANSI/ASTM D2661
Polypropylene UL-1738
Pipe Cement/Primer
PVC ANSI/ASTM D2564
CPVC ANSI/ASTM F493
ABS ANSI/ASTM D2235
Use of cellular core PVC (ASTM F891), cellular core CPVC, or Radel® (polyphenylsulfone) in non-metallic ven ng systems is prohibited.
Covering non-metallic vent pipe and fi ngs with thermal insula on is prohibited.
NOTE: Approved vent and air intake Polypropylene vent materials: Centrotherm InnoFlue® Single Wall Vent System
Table 8: Vent Pipe Lengths
No. of
Elbows
Max. Ver cal or Horizontal (Total) Vent Length
2 in ven ng 3 in ven ng
0 75 (22.9 m) 150 (45.7 m)
1 70 (21.3 m) 145 (44.2 m)
2 65 (19.8 m) 140 (42.7 m)
3 60 (18.3 m) 135 (41.1 m)
4 55 (16.8 m) 130 (39.6 m)
5 50 (15.2 m) 125 (38.1 m)
Excludes vent terminators, termina on elbows, or rain caps.
For details on the vent connec on, refer to “Installing the Vent Pipe” on page 23.
For each 90 degree elbow added, deduct 5 . 45 degree elbows count as 2.5 feet.
Installing the Vent Pipe
WARNING! Improper installa on can
cause nausea or asphyxia on, severe
injury or death from carbon monoxide
and fl ue gases poisoning. Improper
installa on will void product warranty
• When inser ng the pipe into the ex-
haust/intake port, make sure that the
pipe end is cut straight and posi oned
properly under the o-ring to seal the
connec on fi rmly.
• Improper ven ng of this appliance
can result in excessive levels of carbon
monoxide which can result in severe
personal injury or death.
Vent Piping
1
Insert 2 in diameter straight pipe
fully into the exhaust/intake con-
nection ports until fully seated
(See Figure 15). The pipes will insert at a
minimum of 1.5 inches.
WARNING: The exhaust vent pipe
connec on to the water heater must be
fl ush to maintain a proper seal. Check
pipe for a 90° edge before installa on.
DO NOT use a fi eld cut end for the
connec on. Failure to follow can cause
carbon monoxide poisoning or death.
NOTICE: For 3 in Ven ng, install a 2 in x
3 in increaser to convert to 3 in ven ng.
For low clearance installa ons, a 2 in long
sweep elbow may be used. Then 12 in max
length straight pipe may be used to fi t a 2
in x 3 in increaser.
Air Intake for Power Vent Installs: Insert
the male end of a 2 in long sweep street
elbow into the heater’s air intake port.
2
Use a screwdriver to tighten the
clamp. (See Figure 15)
3
Use the supplied self-tapping
screws to secure the venting to
the intake and exhaust ports as
shown in the image on the right. (See
Figure 15)
Power Vent (PV)
Direct Vent (DV)
3 in Pipe
2 in to 3 in
Adapter
2 in Pipe
2 in Pipe
3 in Pipe
2 in to 3 in
Adapter
2 in Pipe
2 in Pipe
2 in Pipe
2 in Pipe
Pipe end
ŶŽƚŇƵƐŚ
ǁŝƚŚďĂƐĞ
Pipe end
ŝƐŇƵƐŚ
ǁŝƚŚďĂƐĞ
Not a
90° edge
džŚĂƵƐƚsĞŶƚ
Pipe
90° edge
džŚĂƵƐƚsĞŶƚ
Pipe
džŚĂƵƐƚ
Intake
Port
Intake Port
džŚĂƵƐƚ
Port
Clamp
Self-Tapping Screw
Figure 15 - Vent Pipe Installa on
Exhaust Vent for
Indoor Installa on
ABS, PVC, CPVC or
polypropylene vent
The Indoor model can be vented with ABS,
PVC, CPVC, or polypropylene (temperature
rated up to 149°F). In Canada, plas c
ven ng must be cer fi ed to ULC S636.
• The maximum length of exhaust ven ng
or intake piping shall not exceed the
lengths listed in Table 8.
• Do not use more than fi ve elbows in a
vent system. For every 90 degree elbow
added, deduct fi ve feet and 45 degree
elbows count as 2.5 . If an elbow(s) is
used in the vent system, deduct each
equivalent length from the Max. vent
length to decide the total vent length.
• When the horizontal vent run exceeds
5 (1.5 m), support the vent run at 3
(0.9 m) intervals with overhead hangers.
• In areas of high rainfall the installa on of
the rain trap may be necessary.
• Slope horizontal ven ng sec ons 1/4
in (6 mm) upwards for every 12 in
(305 mm) toward the termina on or
according to local and state codes, or in
the absence of local or state/provincial
codes, the current edi on of the ANSI
Z223.1/NFPA 54, Na onal Fuel Gas Code
or B149.1, Natural gas and propane
installa on code.
• Do not use ght 90° elbows. Standard
and long sweep elbows are acceptable.
See Figure 16.
Not Recommeded
90° Vent
El
bow
Recommended
90° Sweep
Elbow
90° Long
Sweep
Elbow
Figure 16 - Correct/Incorrect Elbows
Residen al Gas Tankless Water Heater Use and Care Guide • 23
INSTALLATION
24 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
Direct Vent Horizontal Installa on Examples
Hanger
Direct Vent Ver cal Installa on Examples
Fire Stop
Roof
Figure 17 - Vent Confi gura on Examples for Direct Vent
Power Vent Horizontal Installa on Example
Hanger
Power Vent Ver cal Installa on Example
Roof
Flashing
Fire
Stop
Figure 18 - Vent Confi gura on Examples for Power Vent
Typical Ven ng Confi gura ons:
The following are typical ven ng confi gura ons examples.
Residen al Gas Tankless Water Heater Use and Care Guide • 25
INSTALLATION
Table 9: - Vent Termina ons
LOW PROFILE TERMINATION
If used in ver cal
posi on, the
exhaust port must
be placed in the
upper side.
Vent Pipe Size PVC Kit Number IPEX PVC Part Number
IPEX System 1738®
PVC Part Number
2 in 100187903 196984 397984
3 in 100187887 196985 397985
CONCENTRIC TERMINATION
B
A
C
ABC
FGV 2" 29” 16" 2"
FGV 3" 36” 20" 3"
Vent
Pipe
Size
PVC Kit Number
IPEX
PVC Part Number
IPEX System 1738®
PVC Part Number
IPEX System 636®
CPVC Part Number
2 in 100112869 196005 397005 197040
3 in 100112163 196006 397006 197006
POLYPROPYLENE CONCENTRIC TERMINATION
Vent Pipe Size Centrotherm Part Number
2 in ISLPT0202
3 in ISLPT0303
26 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
POLYPROPYLENE TERMINATION TEE
Vent Pipe Size Centrotherm Part Number
2 in ISTT0220
3 in ISTT0320
POLYPROPYLENE RADIUS ELBOWS
Vent Pipe Size Centrotherm Part Number
2 in 45° EXHAUST ELBOW ISELS0245UV
3 in 45° EXHAUST ELBOW ISELS0345UV
2 in 87° INLET ELBOW ISELS0287UV
3 in 87° INLET ELBOW ISELS0387UV
POLYPROPYLENE CONCENTRIC WALL TERMINATION
Vent Pipe Size Centrotherm Part Number
2 in ICWT242*
3 in ICWT352*
*Consult the vent manufacturer for approved concentric / twin pipe adaptors
Vent Termina on Clearances
H
D
E
L
B
V
V
V
V
B
F
C
B
B
B
V
V
V
V
V
X
X
A
J
M
Operable
Fixed
closed
Fixed
closed
Operable
B
Inside corner
detail
G
A
K
V
X
= Vent terminal
= Air supply inlet
= Area where the terminal
ŝƐŶŽƚƉĞƌŵŝƩĞĚ
Regulator/Gas meter
vent outlet
I
Canada Installa ons
1
US Installa ons
2
Direct vent and other than direct vent Direct vent Other than direct vent
A Clearance above grade, veranda, porch, deck, or balcony 1 ft (30 cm) 1 ft (30 cm)
B Clearance to window or door that may be opened 3 ft (91 cm)
1 ft
(30 cm)
4 ft (1.2 m) below or to side
of opening; 1 ft (30 cm) above
opening
C Clearance to permanently closed window 0 0 0
D
Vertical clearance to ventilated soffit located above the vent
terminator within a horizontal distance of 2 feet (61cm) from
the center line of the termination
3 ft (91 cm) 3 ft (91 cm) 3 ft (91 cm)
E Clearance to unventilated soffit 3 ft (91 cm) 3 ft (91 cm) 3 ft (91 cm)
F Clearance to outside corner 2 ft (61 cm) 2 ft (61 cm) 2 ft (61 cm)
G Clearance to inside corner 2 ft (61 cm) 2 ft (61 cm) 2 ft (61 cm)
H
Clearance to each side of center line extended above
meter/regulator assembly
3 ft (91 cm) * *
I Clearance to service regulator vent outlet
Above a regulator within 3 ft (91 cm)
horizontally of the vertical center line of the
regulator vent outlet to a maximum vertical
distance of 15 ft (4.5 m)
**
J
Clearance to non-mechanical air supply inlet to
a building or the combustion air inlet to any other appliance.
3 ft (91 cm)
1 ft
(30 cm)
4 ft (1.2 m) below or to side
of opening; 1 ft (30 cm) above
opening
K Clearance to mechanical air supply inlet 6 ft (183 cm)
3 ft (91 cm) above if within
10 ft (3 m) horizontally.
L
Clearance above paved sidewalk or paved driveway
located on public property
7 ft (213 cm)**
7 ft
(213 cm)
7 ft (213 cm)
M Clearance under veranda, porch deck, or balcony 1 ft (30 cm)***
1 ft
(30 cm)***
1 ft (30 cm)***
*Clearance in accordance with local installation codes and the requirements of the gas supplier.
**A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.
***Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
The vent for condensing water heaters shall not terminate:
• over public walkways; or
• near soffi t vents or crawl space vents or other areas where condensate or vapor could create a nuisance or hazard or cause property damage; or
• where condensate vapor could cause damage or could be detrimental to the opera on of regulators, relief valves, or other equipment.
Notes:
1) In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code
2) In accordance with the current ANSI Z223.1/NFPA 54, National Fuel Gas Code
Residen al Gas Tankless Water Heater Use and Care Guide • 27
INSTALLATION
28 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
Clearances for Sidewall
Termina ons
WARNING! Improper installa on
can result in carbon monoxide
poisoning or death. Follow all local
and na onal codes in regards to
proper termina on clearances.
In the absence of such codes, the
clearances below can be used as
guidelines. Local codes supersede
these guidelines
Mul ple Sidewall Termina ons
An exhaust termina on must be at least:
1 (305 mm) from another exhaust
termina on and 2 (610 mm) from an
inside corner
ŶƟĐŝƉĂƚĞĚ^ŶŽǁůĞǀĞů
džŚĂƵƐƚ
dĞƌŵŝŶĂƟŽŶ
ϮŌ
;ϲϭϬŵŵͿ
ŵŝŶ
ϭŌ
;ϯϬϱŵŵͿ
ŵŝŶ
;ϯϬϱŵŵͿ
ŵŝŶ
/ŶƐŝĚĞ
ĐŽƌŶĞƌ
Figure 19 - Mul ple Sidewall Termina ons
Mul ple DV Sidewall
Termina ons
A direct vent (DV) termina on must be at
least:
• 1 (305 mm) from other DV termina-
ons
• 2 (610 mm) from an inside corner
Inside
corner
ŶƟĐŝƉĂƚĞĚ^ŶŽǁůĞǀĞů
ϮŌ
(610 mm)
min.
ϭŌ
(305 mm)
min.
ϭŌ
(305 mm)
min.
Combined
ŝŶƚĂŬĞĂŶĚ
ĞdžŚĂƵƐƚ
ƚĞƌŵŝŶĂƟŽŶ
Figure 20 - Mul ple DV Sidewall Termina ons
Exhaust and/or direct vent sidewall
termina ons should be at least 2 (610
mm) away from an opposite surface/wall.
Do not place the termina on directly in
front of an opening into a building.
Exhaust
termination
2 ft (610 mm)
min.
Figure 21 - Sidewall Termina on Minimum
Distance to another Structure.
For direct vent sidewall termina ons that use two separate penetra ons for the intake and exhaust, keep the termina on clearances shown in
the diagrams below.
0.5 ft
(159 mm)
min.
Exhaust
Intake
0.5 ft
(159 mm) min.
1 ft (305 mm)
min.
Exhaust
Intake
0.5 ft
(159 mm)
min.
Exhaust
Intake
0.5 ft
(159 mm) min.
1 ft (305 mm)
min.
Intake
Exhaust
Figure 22 - Direct Vent Sidewall Termina ons
Residen al Gas Water Heater Use and Care Guide • 29
Clearances for Roo op
Termina ons
WARNING! Follow all local and na onal
codes in regards to proper termina on
clearances. In the absence of such codes,
the clearances below must be met. Local
codes supersede these clearances. Failure
to observe this warning may result in
severe personal injury or death.
NOTICE: Canadian requirements diff er
from the guidelines in this sec on.
In Canada, follow the current edi on
of B149.1, Natural gas and propane
installa on code as well as local and
provincial codes. Contact your local code
enforcement agency for direc on.
• Exhaust termina ons must be at least 1
(305 mm) away from any obstruc ons.
• Minimum spacing between mul ple
terminals:
• Intake terminals: 1 (305 mm)
spacing between each
• Exhaust terminals: 1 (305 mm)
spacing between each
• The exhaust termina on must be a hor-
izontal distance of at least 2 (610 mm)
from a wall or surface unless specifi ed
diff erently by local code.
• Failure to observe this warning may
result in severe personal injury or death.
INSTALLATION
1 ft (305 mm) min.
Typical PDV Installation
1 ft (305 mm)
min. above anticipated
snow level.
* Anticipated Snow
Level.
1 ft (305 mm) min.
1 ft (305 mm)
min. above anticipated snow level.
3 ft (914 mm) min.
Anticipated Snow Level
ISO VIEW
SIDE VIEW
&ŽůůŽǁĂůůůŽĐĂůĂŶĚŶĂƟŽŶĂůĐŽĚĞƐŝŶƌĞŐĂƌĚƐƚŽƉƌŽƉĞƌƚĞƌŵŝŶĂƟŽŶĐůĞĂƌĂŶĐĞƐ/ŶƚŚĞĂďƐĞŶĐĞ
ŽĨƐƵĐŚĐŽĚĞƐƚŚĞĐůĞĂƌĂŶĐĞƐďĞůŽǁŵƵƐƚďĞŵĞƚ>ŽĐĂůĐŽĚĞƐƐƵƉĞƌƐĞĚĞƚŚĞƐĞĐůĞĂƌĂŶĐĞƐ
Exhaust Vent
Air Intake
Figure 23 - Pitched roof with mul ple ver cal termina ons.
30 • Residen al Gas Water Heater Use and Care Guide
INSTALLATION
1 ft (305 mm) min.
Typical PDV Concentric Installation
1 ft (305 mm) min.
* Anticipated Snow
Level (ASL).
Exhaust Vent
3 ft (914 mm) min.
Anticipated Snow Level
ISO VIEW
FRONT
FRONT
FRONT
&ŽůůŽǁĂůůůŽĐĂůĂŶĚŶĂƟŽŶĂůĐŽĚĞƐŝŶƌĞŐĂƌĚƐƚŽƉƌŽƉĞƌƚĞƌŵŝŶĂƟŽŶĐůĞĂƌĂŶĐĞƐ/ŶƚŚĞĂďƐĞŶĐĞ
ŽĨƐƵĐŚĐŽĚĞƐƚŚĞĐůĞĂƌĂŶĐĞƐďĞůŽǁŵƵƐƚďĞŵĞƚ>ŽĐĂůĐŽĚĞƐƐƵƉĞƌƐĞĚĞƚŚĞƐĞĐůĞĂƌĂŶĐĞƐ
SIDE VIEW
1 ft (305 mm) min.
above anticipated snow level.
1 ft (305 mm) min.
above anticipated snow level.
Exhaust Vent
Air Intake
Air Intake
Figure 24 - Pitched roof with mul ple ver cal concentric termina ons.
Residen al Gas Tankless Water Heater Use and Care Guide • 31
INSTALLATION
Anticipated Snow Level
Anticipated Snow Level
1 ft (305 mm)
min. above anticipated
snow level.
Exhaust Vent
3 ft (914 mm) min.
1 ft (305 mm)
min. above anticipated
snow level.
3 ft (914 mm) min.
ISO VIEW
TOP VIEW
SIDE VIEW
1 ft (305 mm) min.
2 ft (610 mm) min.
from wall or surface.
SIDE VIEW
TOP VIEW
ISO VIEW
Exhaust Vent
3 ft (914 mm) min.
1 ft (305 mm)
min. above anticipated
snow level.
1 ft (305 mm)
min. above anticipated
snow level.
3 ft (914 mm) min.
1 ft (305 mm) min.
2 ft (610 mm) min.
from wall or surface.
&ŽůůŽǁĂůůůŽĐĂůĂŶĚŶĂƟŽŶĂůĐŽĚĞƐŝŶƌĞŐĂƌĚƐƚŽƉƌŽƉĞƌƚĞƌŵŝŶĂƟŽŶĐůĞĂƌĂŶĐĞƐ/ŶƚŚĞĂďƐĞŶĐĞ
ŽĨƐƵĐŚĐŽĚĞƐƚŚĞĐůĞĂƌĂŶĐĞƐďĞůŽǁŵƵƐƚďĞŵĞƚ>ŽĐĂůĐŽĚĞƐƐƵƉĞƌƐĞĚĞƚŚĞƐĞĐůĞĂƌĂŶĐĞƐ
Wall
Typical Flat Roof Terminations
(Both Single and Multiple)
Exhaust Vent
Air Intake
Air Intake
Exhaust Vent
Air Intake
FRONT
FRONT
FRONT
FRONT
FRONT
FRONT
Wall Wall
Wall Wall
Wall
Figure 25 - Flat roof with mul ple ver cal termina ons.
32 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
Exhaust Ven ng for
Outdoor Installa on
1
Turn off power and the gas
supply to the water heater.
Remove the four screws from
the top plate of the water heater as
shown in the fi gure below.
Screws
Figure 26 - Remove top plate screws.
2
Orient the outdoor vent cap as
shown in Figure 27.
Figure 27 - Outdoor Vent Cap secure with
screws.
3
Secure the Outdoor Vent Cap to
the water heater at each corner
with the screws removed earlier.
See Figure 27.
Figure 28 - Control Panel Cover Plate Install.
4
A ach the UIM overlay as shown
in Figure 28.
5
Remove the front cover and
remove the screw on the top le
holding the computer board in
place, press the locking tab and pull the
computer board towards yourself to lower
it on the hinge to access the air inlet plate.
6
Locate the air inlet plate as
shown in Figure 29. Remove and
keep the 3 screws securing it to
the base of the water heater. The plate is
color coded and it should be rotated so
that the yellow side of the plate is rotated
up. Secure with the screws removed
earlier.
INDOOR CONFIGURATION
OUTDOOR CONFIGURATION
Figure 29 - Air inlet plate orienta on op ons
.
7
Connect the water heater to
power. See “Electrical
Connec ons” on page 42.
NOTICE: This water heater comes
equipped with a SJWT rated cord which is
weather resistant and rated for outdoor
use. See “Electrical Connec ons” on page
42.
Outdoor Available
Accessories
It is recommended that a Cartridge
Freeze Protec on Kit be installed if the
water heater is installed outside or in
uncondi oned areas subject to freezing
temperatures.
A pipe cover is available and affi xes to
bo om of heater. It protects plumbing
connec ons to the heater while improving
the appearance of the installa on.
For more informa on see “Available
Accessories” on page 15
Residen al Gas Water Heater Use and Care Guide • 33
INSTALLATION
Gas Supply and Gas
Pipe Sizing
Gas Piping
WARNING! Read the water heater’s
data plate to determine the type of
gas required. Failure to follow these
instruc ons can result in serious injury
or death from explosion, fi re or carbon
monoxide poisoning.
• Ensure that any and all gas regulators
used are opera ng properly and
providing gas pressures within the
specifi ed range shown below. Excess
gas inlet pressure may cause serious
accidents.
• The water heater is set only for Natural
Gas at the factory. If your gas type is
Liquid Propane Gas, gas conversion
shall be required with the included gas
conversion kit by a qualifi ed installer.
Gas piping must be installed according
to local and state/provincial codes, or in
the absence of these codes, the current
edi ons of ANSI Z223.1/NFPA 54, Na onal
Fuel Gas Code in the USA or B149.1,
Natural gas and propane installa on code
in Canada.
• DO NOT a ach the gas line to the water
heater un l a er supply line pressure
tes ng has been completed to avoid any
damage to the water heater.
• The minimum and maximum inlet gas
pressures are:
Table 10: - Inlet Gas Type/Pressure
Natural Gas:
Min 3.5 in W.C. (0.87 kPa)
Max. 10.5 in W.C. (2.62 kPa)
Propane:
Min 8.0 in W.C. (1.99 kPa)
Max. 13.0 in W.C. (3.24 kPa)
Size the gas pipe appropriately to supply
the necessary volume of gas pressure,
and allowable pressure drop required
for the water heater using gas piping
manufacturer instruc ons, local and
state/provincial codes, or in the absence
of these codes, the current edi ons of
ANSI Z223.1/NFPA 54, Na onal Fuel Gas
Code in the USA or B149.1, Natural gas
and propane installa on code in Canada.
Otherwise, fl ow capabili es and output
temperatures will be limited.
• Inlet gas pressures that fall outside
the range of values listed above may
adversely aff ect the performance of
the water heater. These pressures are
measured when the water heater and
all other gas appliance(s) served by the
same gas line are in full opera on.
• Inlet gas pressure must not exceed
the maximum values in Table 10; gas
pressure above the specifi ed range will
cause dangerous opera ng condi ons
and damage to the unit.
• If the gas supply pressure to the heater
is greater than the specifi ed maximum, a
fi eld-supplied regulator is required. The
regulator must lower the gas pressure
within the approved range.
• Install the gas regulator according to the
manufacturer's instruc ons. Some man-
ufacturers may require a certain amount
of straight pipe on the outlet prior to
any addi onal fi ngs.
• The regulator must be sized for the wa-
ter heater's minimum to maximum input
and provide the specifi ed pressures that
are listed on the ra ng plate.
• In the absence of minimum install dis-
tance stated by the regulator manufac-
turer, it is recommended that there is
at least 3 (1 m) of piping between the
regulator outlet and the water heater's
inlet gas connec on.
Gas Connec ons
1
Use a 1/2 in union to connect
gas piping to the water heater's
1/2 in male NPT connection.
2
Install a full port manual gas
shutoff valve between the water
heater and the gas supply line.
3
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 tes ng 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
tes ng of the gas supply piping
system at test pressures equal to or
less than 1/2 psi (3.5 kPa).
4
Always purge the gas line of any
debris and/or water before
connec ng to the gas inlet.
34 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
Natural Gas Supply Piping
Maximum delivery Capacity in Cubic Feet of Gas per Hour (based on IPS Pipe carrying Natural Gas with 0.60 Specifi c Gravity with a Pressure
Drop of 0.5 in W.C.).
Based on Energy Content of 1,000 BTU/
3
: The water heater requires 199
3
/h for the THR-199, 180
3
/h for the THR-180, 160
3
/h for the
THR-160.
The following tables are from ANSI Z223.1/NFPA 54. (Unit: Cubic feet per hour)
Table 11: Natural Gas Table
Pipe Size Length
Diameter
10 ft
(3.0 m)
20 ft
(6.1 m)
30 ft
(9.1 m)
40 ft
(12.2 m)
50 ft
(15.2 m)
60 ft
(18.3 m)
70 ft
(21.3 m)
80 ft
(24.4 m)
90 ft
(27.4 m)
100 ft
(30.5 m)
125 in
(38.1 m)
150 in
(45.7 m)
200 in
(61.0 m)
1/2 in 172 118 95 81 72 65 60 56 52 50 44 40 34
3/4 in 360 247 199 170 151 137 126 117 110 104 92 83 71
1 in 678 466 374 320 284 257 237 220 207 195 173 157 134
1-1/4 in 1,390 957 768 657 583 528 486 452 424 400 355 322 275
1-1/2 in 2,090 1,430 1,150 985 873 791 728 677 635 600 532 482 412
2 in 4,020 2,760 2,220 1,900 1,680 1,520 1,400 1,300 1,220 1,160 1,020 928 794
Propane (LP) supply piping
Maximum Capacity of Propane (LP) Based on 11 in W.C. supply pressure at a 0.5 in W.C. pressure drop. (Unit: kBTU per hour)
Table 12: Propane Gas Table
Pipe Size Length
Diameter
10 ft
(3.0 m)
20 ft
(6.1 m)
30 ft
(9.1 m)
40 ft
(12.2 m)
50 ft
(15.2 m)
60 ft
(18.3 m)
70 ft
(21.3 m)
80 ft
(24.4 m)
90 ft
(27.4 m)
100 ft
(30.5 m)
125 ft
(38.1 m)
150 ft
(45.7 m)
200 ft
(61.0 m)
1/2 in
268 184 148 126 112 101 93 87 82 77 68 62 53
3/4 in 567 393 315 267 237 217 196 185 173 162 146 132 112
1 in 1,071 732 590 504 448 409 378 346 322 307 275 252 213
1-1/4 in 2,205 1,496 1,212 1,039 913 834 771 724 677 630 567 511 440
1-1/2 in 3,307 2,299 1,858 1,559 1,417 1,275 1,181 1,086 1,023 976 866 787 675
2 in 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
Water heater
199,000 BTU/h
Dryer
35,000 BTU/h
Gas meter
Furnace
120,000 BTU/h
Range
65,000 BTU/h
A
B
C
10' (3 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 m)Length
3/4" Pipe size
10' (3 m )Length
1" Pipe size
5' (1.5 m) Length
1-1/4" Pipe size
10' (3 m)Length
1/2" Pipe size
5' (1.5 m)Length
1-1/4" Pipe size
Gas sizing example
(Natural Gas)
Based on Energy Content of 1,000 BTU/
3
:
Divide each appliance's BTU/h requirement by 1,000 BTU/
3
to get the appliance's
3
/h requirement.
Take into account the distance the appliance is from the gas meter, look in the above gas chart to properly size the line.
For sec ons of the gas line supplying gas to more than one appliance (Ex: Point A to Point B), add up the cubic per hour requirements of the
appliances that are being supplied by that sec on, and size to the farthest appliance.
For Example: The sec on 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
3
/hr requirement of 220
3
of gas per hour. The farthest appliance is the range, which is 50 away from the meter. Looking at the
above chart, and under the column of 50 , Sec on A to B needs to be 1 in in order to supply
220
3
.
Residen al Gas Tankless Water Heater Use and Care Guide • 35
INSTALLATION
Gas Conversion
Instruc ons
WARNING! An improper fi eld conversion
could cause poten ally dangerous
condi ons that may cause an explosion or
fi re resul ng in property damage, bodily
injury or both.
This water heater is confi gured for Natural
Gas from the factory. However, if a fi eld
conversion to Propane Gas is necessary,
the conversion kit and instruc ons
supplied with the water heater, and must
be used and installed by a qualifi ed service
agency.
Before you install the components in this
Propane Gas conversion kit, verify the
type of gas that will be used to fuel the
unit.
Water Connec ons
WARNING! Do not use this appliance
if any part has been under water.
Immediately contact a qualifi ed installer
or service agency to replace a fl ooded
water heater. Do not a empt to repair
the unit! It must be replaced!
NOTICE: Do not reverse the hot outlet and
cold inlet connec ons to the water heater.
If you reverse the connec ons, the water
heater will not ac vate properly.
Determine the type of water pipes in
your home. Use fi ngs appropriate for
the type of pipe in your home (copper,
CPVC, or PEX). Do not use iron or PVC
pipe – they are not suitable for potable
water. All pipes, pipe fi ngs, valves and
other components, including soldering
materials, must be suitable for potable
water systems. Also, an automa c air vent
or air separator must be installed when
the water heater operates in a closed loop
system such as a recircula on system.
Trapped air bubbles in the water system
can cause a pump to cavitate or damage
the water heater's heat exchanger. This
equipment must be installed according to
its manufacturer's instruc ons.
• 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.
• A thermal expansion tank or code
approved device to handle thermal
expansion must be and charged to
match the supply pressure as per the
thermal expansion tank manufactures
instruc on.
• Connect the cold water supply using 3/4
inch Na onal Pipe Thread “NPT” to the
fi ng marked COLD.
• For ease of removing the water heater
for service or replacement, connect
the water pipes with a union. We
recommend using a dielectric-type
union (available at your local plumbing
supplier). Dielectric unions can help
prevent corrosion caused by ny electric
currents common in copper water pipes
and can help extend the life of the water
heater.
• Connect the hot water supply using
3/4 inch NPT to the fi ng marked HOT.
Follow the same connec on guidelines
as for the cold water supply.
• In addi on, a manual shutoff valve is
also recommended on the hot water
outlet.
• Double check to make sure the hot and
cold water pipes are connected to the
correct hot and cold water fi ngs on
the water heater.
• If needed, install (or adjust) the home’s
Pressure Reducing Valve.
• Before installing the water heater, fl ush
the water line to remove all debris, and
a er installa on is complete, purge the
air from the line. Failure to do so may
cause damage to the heater.
• There is a wire mesh fi lter within the
cold inlet to trap debris from entering
your heater. This will need to be cleaned
periodically to maintain op mum fl ow.
• Install insula on (or heat tape) on the
water pipes especially if the indoor
installa on area is subject to freezing
temperatures. Insula ng the hot water
and return pipes will reduce heat loss.
• If water hammer is evident install water
hammer arrestors on the inlet side.
• A drain pan, or other means of
protec on against water damage, is
recommended to be installed under the
water heater in case of leaks.
IF YOU HAVE COPPER PIPES:
If your home has copper water pipes, you
can solder the water pipe connec ons
or use compression fi ngs which don’t
require soldering. Compression fi ngs are
easier to install than soldering pipe. Check
with local plumbing offi cials to determine
what types of pipe materials are suitable
for your loca on. Do not use lead-based
solder.
NOTICE: Do not solder pipes while they
are a ached to the water heater. The
water heater contains non-metallic parts
which could be damaged. The proper way
to connect the water heater to copper
water pipes is as follows:
• Solder a short length of pipe (about a
foot or so) to a threaded adapter using
only 95/5 n an mony or equivalent
solder.
• A ach the threaded adapters to the wa-
ter heater’s connec ons (using thread
sealant tape or pipe joint compound).
Connect the home’s water pipes by sol-
dering, keeping the connec ons at the
water heater cool with wet rags.
36 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
Recircula on
Internal Pump
This water heater comes with an
integrated recircula on pump, which is
deac vated by default from the factory.
The water heater has 3 recircula on mode
op ons:
• Recircula on with a dedicated return
line
• Crossover recircula on mode
• On-Demand mode compliant with Cali-
fornia’s Title 24
Details of the opera on are listed below.
In each mode, the heater’s pump only
operates when there is no demand from
the home’s fi xtures. The pump stops when
demand is detected from a plumbing
fi xture.
The internal recircula on pump can
compensate for various plumbing
confi gura ons and the associated pressure
drops, balancing power usage against the
target recircula on fl ow rate. The so ware
has been op mized with a default power
level to operate in the most common
installa ons delivering 1.0 gpm in the
Dedicated Return Line mode or 0.5 gpm
in a Crossover Recircula on mode while
maintaining effi cient opera ons.
NOTE: If a dedicated return line is
installed, a check valve is necessary on the
return line upstream of the tee to the cold
water supply line. See piping layout in
Figure 30 on page 37.
• Recircula on with a Dedicated Return
Line - In this mode, the water heater will
operate the pump in order to keep your
water lines warm, reducing the me it
takes for the hot water to arrive at the
fi xture. The user can con Two Pump
Timer ON periods where the heater will
operate the pump. It is recommended to
set the Pump Timers to ON during mes
when the home is occupied. The water
heater will operate as an on-demand
water heater during Pump Timer Off
periods, though there may be a delay
ge ng hot water to the fi xture. See
“Se ng the Pump Timers” on page 55
to set the Pump Timers.
• Crossover Valve Mode - In this mode, a
“crossover” valve is typically installed at
the home’s furthest fi xture. This valve
will use the home’s cold water line to act
as the return line. The se ngs on the
valve are dependent on the manufac-
turer. For example the typical opera on
is as follows; the crossover valves have
a type of thermal valve that will open
up when the water temperature on the
hot side drops below 95°F (35°C) and
will close when the temperature reaches
105°F (40.5°C). NOTICE: These tempera-
ture values may vary from manufacturer
to manufacturer. Refer to Tables 20 and
21 to set the Crossover Valve Recircu-
la on mode and the Pump Timers. For
manufacturer recommended crossover
valve see “Available Accessories” on
page 15. NOTICE: Func on/compat-
ibilty may vary with other crossover
valves.
• On-Demand Mode - In this mode the
pump will only operate when ac vated
by the user through one of the wireless
push bu ons. A Remote Recircula on Kit
is required see “Available Accessories”
on page 15. This kit consists of one
receiver wired to the water heater and
at least one push bu on. The receiver
can pair with up to 30 push bu ons.
Instruc ons are provided with the
receiver kit. This mode is compliant
with California’s Title 24 Code. In this
mode, the pump will run un l the
inlet water temperature reaches the
deac va on temperature set in mode
A04 for Recircula on with a Dedicated
Return Line or when the crossover valve
closes if in Crossover Recircula on. The
pump will stop if it is s ll running a er 5
minutes.
Table 13: Maximum Pipe Length
Hot Water supply line and
Dedicated Return line
Pipe Diameter Pipe Length
3/4 in 500 ft (152.4 m)
1/2 in 200 ft (61 m)
NOTE: These are equivalent lengths
that includes head loss for elbows,
tees, unions, etc for smooth wall
copper tube. Other water tube
materials have diff erent head
loss characteris cs. When other
materials are used, the installer
shall consult with the water tube
manufacturer to conduct a head loss
calcula on to make sure the installed
pump will fl ow at least 2 gpm.
Please refer to the manufacturer’s
specifi ca on sheet for pump head
loss informa on. An addi onal pump
may be necessary for circula on
systems with longer equivalent pipe
lengths.
External Pump
When installing an external recircula on
pump, care must be taken to properly size
the pump for the applica on. Sizing must
be performed by the installing contractor
or engineer. The following requirements
need to be observed when sizing:
• Size the recircula on pump to fl ow no
less than 2 gpm (7.6 l/m) and no more
than 4 gpm (15.1 l/m) per ac vated
heater. The manufacturer’s suggested
fl ow rate is 3 gpm (11.4 l/m). Refer to
the water heater’s pressure drop chart
on its specifi ca on sheet for losses at
other fl ow rates. Head loss at 3 gpm is
approximately 16.9 . of head (7.3 psi)
The pump should be controlled by a
fi eld supplied aquastat with immersion
probe and an adjustable diff eren al.
The minimum suggested diff eren al is
15°F (8.3°C). NOTE: Running the pump
Residen al Gas Water Heater Use and Care Guide • 37
INSTALLATION
con nuously will reduce the warranty of
the water heater.
• An air elimina on device is suggested
to remove air from the piping system.
Air may cause the recircula on pump to
cavitate and may reduce the water fl ow
rate. These items should be installed per
the manufacturer’s instruc ons.
The installer will need to consider the
size of water tubing, material type, and
fi ngs when determining the pressure
drop of the system to size the recircula on
pump. Note that these characteris cs
vary for each tubing material of the
same nominal size. Refer to the water
tubing manufacturer for pressure drop
informa on that is needed to size the
recircula on pump.
Below is a suggested piping diagram.
Check with local codes and ordinances
for addi onal installa on requirements.
Refer to the water heater manufacturer’s
website for addi onal layouts.
Thermosta c mixing valves may be used
with tankless water heaters. Consult
with the mixing valve manufacturer for
the appropriate mixing valve for the
applica on. Refer to the thermosta c
mixing valve manufacturer for proper
installa on when recircula on is in use.
To reduce the risk of scalding, install
Thermosta c Mixing Valves (temperature
limi ng valves) at each point of use.
COLD
WATER
SUPPLY
EXPANSION
TANK
CHECK
VALVE
HOT WATER TO FIXTURES
BUILDING RETURN
PUMP
TEMP. PROBE
GAS
SHUT OFF
VALVE
Figure 30 - Recircula on Loop Typical Confi gura on
38 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
Combina on Potable
Water and Space
Hea ng
WARNING! This water heater is
suitable for combina on water (potable)
hea ng & space hea ng, and not
suitable for space hea ng applica ons
only.
• This water heater shall not be
connected to any hea ng system or
component(s) previously used with
non-potable water where any chemi-
cals were added to the water hea ng
appliances.
• Toxic chemicals used in boiler treat-
ments such as alcohol, glycerol, and
glycol groups must not be introduced
into the water system.
• When the system requires water
for space hea ng at temperatures
higher than required for other uses,
thermosta c mixing valves must be
installed at each point-of-use. Water
temperatures over 125°F (52°C) can
cause severe burns instantly or death
from scalding. Failure to observe
these warnings could result in severe
personal injury or death.
Care must be taken by the installing
contractor or design engineer to size the
components of the system appropriately
for fl ow rate and temperature. In
addi on to sizing the water heater
for the domes c potable water, the
installer must size the water heater
to provide the fl ow rate required by
the manufacturer of the air handler.
Refer to the air handler manufacturer’s
instruc ons and specifi ca on documents
for this fl ow rate. The pump, fi eld
supplied or provided by the air handler
manufacturer, must be able to provide
this minimum fl ow rate.
The water heaters internal circula on
pump shall not be used in this
applica on.
When sizing the pump, the installer must
take into account the pressure drop of
the following:
• Hydronic Air Handler. Refer to the
manufacturer for this informa on.
• Water Heater. Refer to the water
heater’s specifi ca on sheet for pres-
sure drop informa on. At 3 gpm, the
approximate head loss is 16.9 . of
head (7.3 psi).
• Water Tubing Size, Length, and
Material. Refer to the water tubing
manufacture for pressure drop
informa on as it diff ers from one
material to the next and at diff erent
sizes. There may be addi
onal
applica on requirements by the water
tubing manufacturer.
• Fi ngs: Refer to the fi ng
manufacturer for pressure drop
informa on.
Addi onal considera ons are:
• Installing an air elimina on device to
remove air that may cause cavita on in
the pump.
• A priority control device, such as a fl ow
switch, to priori ze the domes c water
system over the hea ng system.
• Thermosta c mixing valves at each
point-of-use. Refer to the mixing valve
manufacturer for proper selec on and
installa on.
Figure 31 is a suggested piping layout.
The installer must properly install the
system per manufacturer’s instruc ons
and local codes.
GAS
AIR HANDLER
TEMPERED HOT
WATER TO FIXTURE
EXPANSION
TANK
COLD
WATER
SUPPLY
CHECK
VALVE
SHUT OFF
VALVE
PUMP
THERMOSTATIC MIXING
VALVE
CHECK
VALVE
Figure 31 - Air Handler/Recircula on Loop Confi gura ons
Residen al Gas Tankless Water Heater Use and Care Guide • 39
INSTALLATION
Dual Purpose Water
Hea ng for the State
of Massachuse s
• This sec on applicable to
Massachuse s (USA) installa ons only.
Not applicable in Canada.
• Priority Control Devices such as a fl ow
switch, an Aquastat or other electronic
controller can be used to priori ze
the domes c water system over the
hea ng system.
• Follow all local codes, or in the ab-
sence of local codes, follow the current
edi on of the Na onal Standard Code,
ANSI Z21.10.3, CSA 4.3.
• The illustra on below is a concept
design only. The reference to the
1/8-inch hole in the check valve is only
required in the State of Massachuse s.
There are a wide variety of varia ons
to the applica on of controls and
equipment presented. Designers
must add all the necessary safety
and auxiliary equipment to conform
to code requirements and design
prac ce. For more details, contact the
manufacturer or local code authority.
120 VAC
switch or
outlet
Hot water outlet
Check valve
Electronically controlled
every 6 hours for 60
seconds. Wire to
product approved pump
(used with air-handler)
Cold water supply
Discharge must
comply with local and
state codes. Cannot
be common vented
with other appliances
An approved temperature and pressure
water heater model used
Check valve will have
1/8-inch hole drilling
Atmospheric
vacuum
breaker
valve
Pressure
gauge
Apply correct thermal
expansion tank-size
Check valves
Cold water inlet
Gas inlet
Water Drain
plug
Hot water
supply and
return to
System installed with reverse
Suggested but not required by
248 CMR
50’-0” maximum distance from
water heater to fan coil.
(Developed length) Not including
NSF-61 product
approved pump
must be installed below
the top of the water heater
as per manufacturer’s
Piping loop
between water
heater and fan
coil shall be in
compliance with
248 CMR
Tempered water to
meet temperature
requirements of 248 CMR
All water piping should be insulated
in accordance with 780 CMR
The ƌĞĐŝƌĐƵůĂƟŽŶ pump is tŽ prŽvide ŶŽ less ƚŚĂŶ 2 GPM (7.5 >ŵŝŶͿ ĂŶĚ ŶŽ ŵŽƌĞ ƚŚĂŶ 4 GPM (15 >ŵŝŶͿ ƚŚƌŽƵŐŚ
each ĂĐƟǀĂted ƵŶŝƚ ŝŶ the system.
Ball
Valve
IsolaƟŽn
Val ve
Unions
ƵƚŽŵĂƟĐƚĞŵƉĞƌŝŶŐĚĞǀŝĐĞ
ƌĞĐŽŵŵĞŶĚĂƟŽŶƐ
;DĂƐƐĂĐŚƵƐĞƩƐĞŶĞƌŐLJĐŽĚĞͿ
,ĞĂƟŶŐŽŝů
ƉůƵŵďŝŶŐĮdžƚƵƌĞƐ
ĂĐƟŶŐĂƋƵĂƐƚĂƚƚŽƐŚƵƚŽīĨĂŶ
ĐŽŝůŝŶŚĞĂƟŶŐƵŶŝƚ
ƉƵŵƉƟŵĞƌĐƟǀĂƚĞƐ
ƌĞůŝĞĨǀĂůǀĞdŝĞƚŽůŽĐĂƟŽŶĂƉƉƌŽǀĞĚďLJ
ůŽĐĂůĐŽĚĞƐĂŶĚŵƵƐƚŵĞĞƚdhƌĂƟŶŐŽĨ
dͲŚĂŶĚůĞŐĂƐƐŚƵƚŽīǀĂůǀĞ
ĮůƚĞƌ
ŝŶĐůĂƉƉĞƌ;ŽƉƟŽŶĂůͿ
^ŚƵƚŽīǀĂůǀĞƐ
^ŚƵƚŽīǀĂůǀĞƐ
ŚĞĂƟŶŐĐŽŝů
dŚĞƌŵŽƐƚĂƟĐŵŝdžŝŶŐǀĂůǀĞ
ƉĞƌĂƉƉůŝĐĂƟŽŶ
^ŚƵƚŽī
Figure 32 - Diagramma c Layout of Radiant Hea ng and Domes c Water Heater
40 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
X3® Technology
WARNING! DO NOT operate water
heater un l either the X3® Cartridge or
Bypass cartridge has been installed into
the manifold located on the underside
of the water heater cabinet. Failure to
do so may result in leaks and poten al
property damage.
This water heater may be equipped with
X3® Scale Preven on Technology to
inhibit scale forma on within the heat
exchanger tubing of this unit. Part of the
X3® Technology’s an -scale protec on
comes from the special X3® Cartridge
media. The X3® Cartridge must be
installed into the manifold located on the
underside of the heater cabinet prior to
opera on of the unit (shown as follows).
X3® Scale Preven on Technology
reduces the forma on of scale in the
heat exchanger, extending the opera ng
life of the unit in typical potable water
installa ons. Specifi c water condi ons
may impact the effi ciency of X3®, such as
excessive iron or manganese levels.
X3
®
Cartridge
Bypass
Cartridge
Figure 33 - X3® & Bypass Cartridges
X3® Cartridge Installa on
1
Remove the plug assembly
installed into the manifold
located on the underside of the
water heater cabinet. Properly dispose
of plug assembly materials.
CAUTION! Water may be present
in the manifold. Place a bucket under
the water heater cabinet to collect any
residual water.
2
Locate the three (3) screws
located in the hardware bag
that is located on the top of the
heater carton. Set the one M4-12mm
screw and two M4-25mm screws aside
in a safe place.
3
Locate the X3® Cartridge
provided with the water heater.
NOTICE: Inspect o-rings for damage
or debris. Handle with care and verify
lubricant has been properly applied to
o-rings.
4
Insert the X3® Cartridge into
manifold and secure with the
two long screws and one short
screw previously set aside in Step 2.
NOTICE: The X3® cartridge is keyed to
only install in one direc on. Align the
on the cartridge with the on the
manifold. When inser ng the cartridge,
push up un l the screw holes align.
Some resistance is normal. See Figure
34.
Insert and snug all three screws by hand.
Use a screwdriver to ghten the two
B
screws fi rst and lastly ghten screw
A
. DO NOT use a drill or impact driver to
ghten the screws.
A BB
A
B
B
A
B
B
ALIGN
X3
®
CARTRIDGE
MANIFOLD
Figure 34 - X3® Cartridge Installa on
X3® Cartridge Removal
1
Disconnect power to the water
heater by unplugging it or by
turning off the circuit at the
breaker box.
2
Close the cold inlet water
valve.
3
Open all hot water taps in the
house. When the residual
water fl ow has ceased, close all
hot water taps.
4
Remove the two long and one
short screws securing the X3®
Cartridge to the manifold
located on the underside of the water
heater cabinet. Set the screws aside in a
safe place for re-installa on. Place a
bucket under the water heater cabinet
to collect any residual water. Note the
order of the screws when removing
them. Reference Figure 34.
5
Pull down to remove the X3®
Cartridge from the water
heater.
NOTICE: The X3® Cartridge will be full
of water. Use cau on not to lt the
cartridge un l the water has been
drained.
Bypass Cartridge
If the water heater does not use the X3®
Scale Preven on Technology, confi rm
the bypass cartridge has been properly
installed before opera ng the water
heater.
NOTICE: Bypass cartridge installs the
same way as the X3® cartridge, however
it is not keyed.
Pressure Relief Valve
WARNING! Hot water could be
released. Before opera ng the pressure
relief valve manually, check that it will
discharge in a safe place. If water does
not fl ow freely from the end of the
discharge pipe, turn the gas supply and
power OFF and call a qualifi ed person to
determine the cause.
Refer to the pressure relief valve
manufacturer's instruc ons for
inspec on and maintenance
requirements.
Residen al Gas Water Heater Use and Care Guide • 41
INSTALLATION
6” (152.4 mm)
Maximum
Discharge Pipe
Figure 35 - Discharge Pipe
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.
• An approved pressure relief valve is
supplied with the X3® models. An ap-
proved pressure relief valve shall be fi eld
supplied for the M models.
• The discharge piping for the pressure
relief valve must be directed so that the
hot water cannot splash outward and
cause damage or personal injury.
• A ach the discharge tube to the pres-
sure relief valve and run the end of the
tube to within 6 in (152 mm) from the
fl oor for US installa ons and 12 in (305
mm) for Canadian installa ons. This
discharge tube must allow free and com-
plete drainage without any restric ons.
• If the pressure relief valve discharges
periodically, this may be due to thermal
expansion in a closed water supply
system. Contact the water supplier or a
local plumbing professional on how to
correct this situa on. Do not plug the
pressure relief valve.
The pressure relief valve must be
manually operated annually to check
for correct opera on. Before opera ng
the valve manually, check that it will
discharge in a place for secure disposal.
• No valve must be placed between the
relief valve and the water heater.
• If another pressure relief valve is used or
needs to be replaced, it must meet the
following:
• The pressure relief valve must
conform to local codes.
• The discharge capacity must be at
least 199,000 BTU/h for the THR-
199 model, 180,000 BTU/h for the
THR-180 model,160,000 BTU/h for
the THR-160 model,
• The pressure relief valve needs to
be rated for a maximum of 150 psi
(1 MPa).
Condensate Drain
• Follow all code requirements of the local
authority on condensate neutralizers
and whether or not they are required for
the installa on.
• Discharge condensate (acidic water)
in accordance with all local codes and
common safety prac ces.
• Install minimum 1/2 in corrosion resis-
tant pipe, such as PVC, for the conden-
sate drain line. Do not use metal pipe.
• The condensate drain does not require
a trap.
• Maintain a downward slope on the drain
line(s), including installa ons in which
the drain is not directly below the water
heater.
• If a neutralizer is installed, a fi eld-
supplied overfl ow bypass fi ng (tee/
wye) is recommended.
• Do not connect the condensate drain
line directly to a condensate pump.
If the drain line is required to have
bends, ensure that there are no kinks
that will restrict the fl ow of condensa-
on.
• The condensate drain is at atmospheric
pressure (non-pressurized) and
therefore must be allowed to drain
freely with gravity only. Ensure that the
condensate drain tube is not plugged
or blocked, and ensure that it slopes
downward to allow condensate to fl ow
freely. All por ons of the condensate
drain (neutralizer and drain tube)
must be at a lower eleva on than the
water heater to prevent condensate
water from building up inside the heat
exchanger.
• Condensate cannot be eff ec vely
neutralized if the neutralizer elements
have been completely consumed. If this
happens, condensate will remain acidic
and can possibly cause damage to items
such as pipes, concrete, etc., if drained
improperly.
• The actual life of the neutralizer may
vary, depending on the applica on and
usage. Replace the cartridge when the
condensate pH goes below 6.0.
• All preventa ve measures and safety
prac ces must be adhered to when
draining condensate. The manufacturer
will not be responsible for any damage
caused by condensate.
• A drain pan, or other means of
protec on against water damage, is
recommended to be installed under the
water heater in case of leaks.
Printed Circuit Board
Ba ery
WARNING! Working on an energized
circuit can result in severe injury or death
from electrical shock.
This heater uses a type 2032 ba ery to
store the clock’s me during a power
outage. When the ba ery’s voltage is
low, an error code will fl ash on the water
heater’s display to indicate the ba ery
should be replaced.
This ba ery only stores the clock’s me
during a power outage. All other se ngs
are saved in the PCB’s memory.
Follow the instruc ons below to ac vate
the ba ery before the fi rst use of the
water heater.
1
Ensure the water heater is NOT
connected to any electrical
power source. The unit must
NOT have power to perform the next step.
2
Remove the front cover.
3
Removed the clear plas c cover
over printed circuit board. Keep
this cover for installa on a er
the ba ery is ac vated.
4
Locate the “coin” style ba ery
slot on the lower part of the PCB
shown in Figure 36
PCB
Batter
y
Figure 36 - Ba ery loca on on PCB
5
Remove the small tab from the
ba ery that is blocking its
connec on. Once the tab is
removed make sure the ba ery is fully
seated in the connector.
6
A er this step you may proceed
to connect the water heater to
electrical power. NOTE: follow
these steps to replace the ba ery when it
is depleted.
Electrical Connec ons
WARNING! Working on an energized
circuit can result in severe injury or death
from electrical shock.
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 a 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.)
• This water heater comes equipped
with a SJWT rated cord which is
weather resistant and rated for
outdoor use.
3
The water heater can be hardwired
or plugged into an outlet with the
correct voltage listed above using
the supplied power cable already attached.
4
The use of a surge protector is
recommended in order to
protect the unit from power
surges.
Plug-in Connec on
1
The water heater should be
plugged into a 120VAC, 60 HZ
ground electrical outlet.
Hard Wired Connec on
NOTE: Follow the steps below if the
power supply must be hardwired to the
water heater. Otherwise, you may skip
this section.
1
Remove and keep the screws
securing the front cover, then
remove it.
2
Remove and keep the screw in
the upper le corner of the
printed circuit board.
3
Depress the latch in the upper
right corner of the printed circuit
board and lower it.
4
Locate the system power cord
using Figure 37. Cut the wires at
the loca on shown in Figure 37.
Figure 37 - System power cord cut loca on.
5
Remove the screws securing the
power cord to the bo om of the
water heater.
6
Remove the power cord from the
bo om of the water heater and
install a strain relief connector in
the opening.
42 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
Residen al Gas Tankless Water Heater Use and Care Guide • 43
INSTALLATION
7
Make the electrical connec on
to the water heater. Follow all
local codes or in the absence of
local codes, with the Na onal Electrical
Codes: ANSI/NFPA 70 in the USA.
8
Verify all electrical connections
are secure.
9
Replace the front cover
and turn on power to the water
heater.
10
Follow the instructions in the
Getting Started section of this
manual.
Cascade System
The Cascade System allows up to 12
heaters of the same input to be linked in
a Parent/Child confi gura on. Do not link
heaters of diff erent input rates together.
The Cascade System will ac vate heaters
based on the system fl ow rate demand.
When system demand increases or
decreases, the cascade system will
ac vate/deac vate heaters as needed to
balance fl ow through the heaters.
The Parent heater determines when to
ac vate/deac vate heaters. The order
of heater ac va on is set by the Parent
heater and will sequence the heaters in
order from the least combus on hours to
the most. This allows for even opera on
of all the water heaters in the cascade
system. The heaters will deac vate in
the reverse order that they are ac vated,
meaning if Child Heater 11 was the last to
turn on, it will be the fi rst to turn off when
system demand decreases. The Parent
heater will reorder the sequence on a
weekly basis.
The new sequence of ac va on will
start with the heater that has the
least combus on hours to the most.
Each heater will ac vate based on
predetermined fl ow rate factors. These
factors vary based on heater model.
Contact the heater manufacturer for
addi onal informa on.
In a recircula on system, only 1 pump will
operate. The pump in the water heater
sequenced to ac vate fi rst will operate.
The pump opera on will rotate to the fi rst
ac vated heater during each sequence.
The pump se ngs only need to be set on
the Parent water heater.
If any child heater encounters an error
code, the cascade system will bypass
that heater and con nue to operate. If
the Parent heater loses power, then the
cascade system deac vates. The user will
need to change the se ngs of one of the
other heaters to be the Parent or resolve
the issue of the Parent heater.
WARNING! Working on an energized
circuit can result in severe injury or death
from electrical shock.
1
The Cascade system should be
configured with the Parent water
heater as either the first or last
in the series of water heaters connected
to the cold water supply. The Child units
will follow sequentially. See Figure 39.
2
Before proceeding, disconnect
electrical power to all water
heaters in the Cascade
configuration.
3
Remove the front covers and
keep the two screws from both
the Parent and Child water
heaters for re-installation.
4
On the Parent water heater lift
the plastic clip locking the
control panel in place and lower
it down out of the way.
5
Remove and keep the clear
plastic covers over the Printed
Circuit Board (PCB).
6
On the bo om of the water
heater locate the rubber access
grommet. Route the single
harness end of the Cascade Linking Cable
through the bo om and around to the
circuit board.
NOTICE: The cable should be routed under
the circuit board assembly to prevent
strain to the wiring harness.
Rubber Grommet
Figure 38 - Bo om of water heater - Grommet.
7
Use Figure 39 as a reference to
locate the connection point for
the Parent Cascade Unit. Use the
single harness end of the Cascade Linking
Cable to make the initial connection.
8
Follow steps 4-6 to route the
double harness end of the
Cascade Linking Cable to the
printed circuit board on the first Child
water heater.
9
If more than one Child water
heater is used then route the
single harness end of the second
Cascade Linking Cable through rubber
grommet on the bo om of the fi rst Child
water heater and connect it to the open
harness on the fi rst Cascade Linking Cable
as shown in Figure 39.
10
Once all connections are made,
the water heaters must be
assigned their position in the
system. Turn on the power supply to all of
the water heaters, making sure there is no
water flow.
11
On the Parent water heater
simultaneously press and hold
the SETTING and UP bu ons
un l C00 appears. See Table 18 on page
52.
44 • Residen al Gas Water Heater Use and Care Guide
INSTALLATION
Parent Unit
Child UnitChild Unit
Child Unit
CWS
HWS
Gas
Supply
Building Return
Cascade
Linking
Cable
Parent Unit
Child Unit
Child Uni
t
C
hild Uni
t
Single
Harness
End
Double
Harness
End
Figure 39 - Mul Unit Cascade Confi gura on
12
Press the UP arrow button to
reach the C13 option, then press
SETTING button to enter that
option.
NOTE: C13 defines the number of Child
water heaters that will be connected to
the parent unit.
Enter the number of Child water heaters
attached to the parent water heater
and press Settings to load the number
to memory. For example, if the system
consists of four total water heaters, then
enter 3 for three child heaters into C13.
Press the SETTING button again to return
to normal operation.
13
After the Parent water heater is
configured, the Child water
heaters must be configured.
Perform the following steps on each Child
water heater.
14
On each Child unit’s UIM, press
and hold both the SETTING and
UP buttons until C00 appears.
15
Press the UP arrow button to
reach the C14 option, then press
the SETTING button to enter
that option.
NOTICE: C14 defines the number assigned
to each Child water heater connected to
the parent water heater.
16
Enter number 2 for the first
Child water heater and press the
SETTING button to load the
number to memory. Repeat this step
assigning a sequencial number at each
additional Child water heater.
17
Press and hold the SETTING
button again to return to normal
operation. NOTICE: A maximum
11 Child water heaters can be connected
to a Cascade System of 12 total water
heaters.
18
Verify all electrical connections
and conduit connections are
secure.
19
Follow the instructions in the
Getting Started section of this
manual.
Residen al Gas Water Heater Use and Care Guide • 45
INSTALLATION
Accessory Connec ons
This system supports up to three
accessories connected in series. NOTE:
If mul ple water heaters are used in a
Cascade confi gura on, all accessories
must be connected in series to the parent
unit.
Follow the accessory kit instruc ons to
access the control board.
Each accessory has a both a fi ve pin
female connector and a sec on of cable
with a fi ve pin male connector on the
end. See Figure 40 The male connector
connects to the control board or to the
next accessory in the series. The fi ve
pin female connector allows another
accessory to connect and create a series.
Reference the fi gure below when crea ng
a series of accessories. If the length of
the accessories cord is not long enough,
communica on cables can be purchased
to extend the length. These cables are
available in 10
(3 m) and 32 (10 m) lengths. Connect
the single fi ve pin connector on
communica on cable to the fi ve pin
female connector on the accessory. The
maximum wire length from the water
heater (parent in a Cascade System) to the
furthest accessory is 100 (30 m).
Wi-Fi Module
Remote
Recirculation
Receiver
Wall
Printed
Circuit
Board
Remote
Temperature
Controller
Accessory 5
Pin Female
Accessory 5
Pin Male
Figure 40 - Accessories installed in series
46 • Residen al Gas Water Heater Use and Care Guide
FOR YOUR SAFETY,
READ BEFORE
OPERATING
WARNING! 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 instruc ons.
• If you cannot reach your gas supplier,
call the fi re department.
• Failure to observe these warnings could
lead to fi re or an explosion, resul ng in
severe injury or death.
ᅚ Check the GAS and WATER
CONNECTIONS for leaks before fi ring
unit for the fi rst me.
ᅚ 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 qualifi ed
service technician. Forced repair
may result in a fi re or explosion due
to gas leaks.
ᅚ Be sure to check for the presence
of leaking gas toward the bo om
of the unit because some gases
are heavier than air and may se le
towards the fl oor.
ᅚ Check the GAS PRESSURE. Refer to
“Gas Supply and Gas Pipe Sizing” on
page 33.
ᅚ Check for PROPER VENTING and
COMBUSTIBLE AIR to the water
heater.
ᅚ Purge the GAS and WATER LINES to
remove any air pockets.
ᅚ Do not use this appliance if any part
has been under water. Immediately
contact a qualifi ed installer or
service agency to replace a fl ooded
water heater. Do not a empt to
repair the unit! It must be replaced!
Start-up Instruc ons
Read and understand these direc ons
thoroughly before a emp ng to start-up
the water heater. Make sure the water
is plumbed correctly before a emp ng
to start the water heater. Check the data
plate on the right side of the water heater
to ensure the correct gas type. Do not use
this water heater with any gas other than
that for which the heater is confi gured. If
you have any ques ons or doubts, consult
your gas supplier or gas u lity company.
NOTICE: A newly installed water heater
will have air in the gas line. It may take
several a empts to clear all the air from
the gas line.
1
Make sure the manual gas valve
for the water heater’s supply line
is ON.
2
Plug the water heater into a
grounded 120 VAC outlet or
activate the breaker/disconnect,
if the water heater is hardwired.
3
The user interface will display
the current temperature setting.
The default is 120°F.
4
To change the set temperature
press the “UP” or “DOWN”
buttons to raise or lower the
temperature. See “Temperature
Adjustment/Setting the Temperature” on
page 49.
Shut-Down Instruc ons
1
Press the “ON/OFF” button and
wait for the display to shut-off.
NOTICE: The power button on
the water heater and remote DOES NOT
disconnect power to the water heater. You
must physically disconnect power to the
water heater.
Emergency Shut-Down
Should overhea ng occur or the gas
supply fail to shut off follow these steps.
1
Turn off gas supply to the water
heater at the manual shut-off
valve.
2
Press the “ON/OFF” button on
the water heater.
3
Disconnect power to the water
heater by unplugging it or by
turning off the circuit at the
breaker box, as appropriate.
4
Call a qualifi ed person (licensed
plumber, authorized gas
company personnel, or
authorized service technician for
assistance.
OPERATION
Residen al Gas Water Heater Use and Care Guide • 47
FOR YOUR SAFETY READ BEFORE OPERATING
OPERATING INSTRUCTIONS
TO TURN OFF GAS TO APPLIANCE
BRÛLURE
BURN
CHAUDECHAUDE
HOTHOT
CHAUDE
HOT
DANGER
WA
RNING:
Cancer and Reproductive Harm - www.p65warnings.ca.gov
California Prop 65:
DANGER
Read and follow water heater warnings and instructions. If the owner’s manual is missing, contact the
retailer or manufacturer.
Flammable Vapors
WARNING:If you do not follow these instructions exactly, a fire 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
floor because some gas is heavier than air and will settle on the floor
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.
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 qualified service technician. Force or attempted repair may
D. 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!
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 five (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 shutofff valve located on the outside of the unit to the closed position.
Vapors from flammable liquids will explode and catch fire causing death or severe burns.
Do not use or store flammable products such as gasoline, solvent s or adhesives in the same room or area
near the water heater.
Keep flammable products:
1. Far away from heater
2. In approved containers
3. Tightly closed and
4. Out of reach of children.
Vapors:
1. Cannot be seen.
2. Are heavier than air.
3. Go a long way on the floor.
4. Can be carried from other rooms to
the main burner by air currents.
Water heater has a main burner, which may come on at any time and will ignite flammable vapors.
Installation: Do not install water heater where flammable products will be stored or used unless the main
burner is at least 18 in (457 mm) above the floor. This will reduce, but not eliminate the risk of vapors being
ignited by the main burner.
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. To reduce the risk of scalding, install Thermostatic Mixing Valves (temperature limiting valves) at each point of use.
6. 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.
7. Use this heater at your own risk. Test the water before bathing or showering. Do not leave children or an infirm
person unsupervised. See your local water supply company [plumbing hardware retailer] for temperature limiting
valves that are available.
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 specified 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 flow.
Before operating the pressure relief valve manually, check that hot water coming out of the relief valve will discharge
in a safe place to avoid contact with hot water and water damage.
See Installation Manual heading “PRESSURE RELIEF VALVES” for installation and maintenance of relief valve
discharge line and other safety precautions.
Figure 41 - Ligh ng Instruc ons
OPERATION
1 2
ON OFF
PM
AM
A
B
C
D
E
F
G
H
I
J
K
L
M
Figure 42 - User Interface Display Diagram
Table 14: User Interface Display
Item Descrip on
A Water Flow Detected
B Pump is Opera ng
C Flame Detected
D Pump Timer 1 & 2 Ac ve
E Pump Bu on
F Time Bu on
G Up & Down Bu ons
H Opera on ON/OFF Bu on
I Se ng Bu on
J Pump Timer ON/OFF Indicators (only shown when se ng the Pump Timers)
K Standby Mode
L AM/PM for Time & Pump Timer Se ng
M Display
48 • Residen al Gas Tankless Water Heater Use and Care Guide
OPERATION
Residen al Gas Tankless Water Heater Use and Care Guide • 49
OPERATION
Temperature Adjustment/Se ng the Temperature
With the installa on steps completed, you may adjust the water heater’s temperature se ng if desired. The water temperature set point
is factory set to 120°F (49°C). The temperature set point may be increased or decreased in increments by simply pressing the “UP” bu on
or the “DOWN” bu on. To set the water heater to a temperature above 125°F (52°C), follow the procedure below.
Opera on
Screen on the Controller
Built-in Controller
1 Turn on the 120 VAC power supply to the water heater.
2 Press the DOWN bu on to decrease the water temperature.
3
Press the UP button to increase the water temperature.
WARNING! Higher temperatures increase the risk of scalding, but even at 120 °F (50 °C),
hot water can scald (See Table 3).
NOTE: You can only increase the water temperature to 125°F. Addi onal steps are required to
increase the temperature above 125°F.
4
To raise the temperature above 125°F, press and hold the SETTING button for 5 seconds then
release. The display will alternately flash A00 and 125°F.
4a Press the SETTING button again. The temperature setting will flash. You can increase the
temperature above 125°F.
4b Press the UP button to set the desired temperature.
4c Press and hold the SETTING bu on to return the display to normal opera on. The new set
temperature will appear in the selected unit
(Example: 130°F).
4d The display should show the updated temperature.
50 • Residen al Gas Tankless Water Heater Use and Care Guide
OPERATION
Unit Conversion Mode
Table 15: Water Heater Temperature Set Points
°F
100 102 104 106 108 110 115 120* 125 130 135 140
°C 38 39 40 41 42 43 46 49* 52 54 57 60
Units of measure can be changed from Imperial to Metric and vice versa. For example, temperature can be changed from
°F to °C. Flow rate will also change from gallons per minute to liters per minute when this se ng is changed. Follow this procedure to change
this se ng.
Table 16: Unit Conversion
Opera on
Screen on the Controller
Built-in Controller
1. Turn on the 120 VAC power supply to the water heater.
2. Press the ON/OFF bu on on the controller in order to turn the controller on.
3 The set point temperature will display as shown in the picture on the right (Example: 120°F).
4 Press and hold the SETTING bu on for 5 seconds to access the water heater A Mode.
5
The display will show code A00. Press the UP bu on once to display code A01. Press the
SETTING bu on to show the current temperature se ng. The temperature will fl ash.
6 Press the UP bu on to alternate between F (Fahrenheit) and C (Celsius).
7 Press the SETTING bu on to execute the change.
Residen al Gas Tankless Water Heater Use and Care Guide • 51
OPERATION
8
Press and hold the SETTING bu on to return the display to normal opera on. The new set
temperature will appear in the selected unit
(Example: 49°C).
Confi gura on Mode (A Mode)
You can confi gure the water heater to accommodate your applica on from A Mode. Follow the procedure below to access A Mode:
1. Press and hold the SETTING bu on for 5 seconds to access A Mode.
2. Press the UP bu on or the DOWN bu on to search for the desired A Code.
3. If applicable, press the SETTING bu on to adjust the value. When the se ng fl ashes, use the UP or DOWN arrows to change the se ng.
4. Press the SETTING bu on again to confi rm the new value selected is correct.
5. Press and hold the SETTING bu on for 5 seconds to return the display to normal opera on.
Table 17: A Table Se ngs
CODE DESCRIPTION OPTIONS
A00 Set Temperature Se ng (for High Temp.)
°F
°C
125 130 135 140
52 54 57 60
A01 Temperature Unit
°F
°C
°F, °C
A02 Recircula on Interval Timer 5, 10(default), 15, 20, 25, 30, 40, 50, 60 min
A03 Pump Turn On Temperature from Set Point
°F
°C
-10 -15 -20 (default) -25 -30 -35 -40
-6 -8 -11 (default) -14 -17 -19 -22
A04 Pump Turn Off Temperature from Set Point
°F
°C
-5 -10 (default) -15 -20 -25 -30 -35
-3 -6 (default) -8 -11 -14 -17 -19
A05 Recircula on Mode
0:
1:
No recircula on (default)
Recircula on Ac ve
A06 Recircula on Type
0:
1:
Dedicated Return Line (default)
Crossover Valve
A07 CA Title 24 Mode
0:
1:
Pump Timer Control (default)
On Demand Control - CA Title 24
Confi gura on Mode (C Mode)
You can confi gure the water heater to accommodate your applica on from C Mode. Follow the procedure below to access C Mode:
1. Press and hold the “UP” bu on and the “SETTING” bu on for 5 seconds to access C Mode.
2. Press the “UP” bu on or the “DOWN” bu on to search for the desired C Code.
3. If applicable, press the “SETTING” bu on to adjust the value of the C Code using the “UP” and “DOWN” bu ons. The value will fl ash.
4. Press the “SETTING” bu on again to confi rm the new value selected is correct.
5. Press and hold the “UP” bu on and the “DOWN” bu on for 5 seconds to return the display to normal opera on.
52 • Residen al Gas Tankless Water Heater Use and Care Guide
Table 18: C Table Se ngs
CODE DESCRIPTION OPTIONS
C01 Eleva on Se ngs in Feet (meters)
0:
1:
2:
3:
0 – 1,999 (default) (0 - 609)
2,000 – 5,399 (610 - 1,645)
5,400 – 7,699 (1,646 - 2,347)
7,700 – 10,100 (2,347 -3,078)
C03 Gas Type
0:
1:
Natural Gas (default)
Propane
C07 Power Frequency
60: 60Hz (default)
C13
Number of Child Units in
Cascade System
0:
1-11:
No Cascade System (default)
Iden fy Number of Child Units. This ac vates the Cascade System
C14
Cascade System Heater ID
Number
1:
2-12:
Parent Heater (default)
Individually set each child unit per user preference
C15 Descaling Mode
Off :
dScL:
No Descale (default)
Ac vate Descale Mode
Se ng the Clock
Table 19: Clock Se ng
Set the Time on the Water Heater Built-in Controller
1. Turn on the 120 VAC power supply to the water heater.
2.
Simultaneously Press and Hold the TIME & SETTING bu ons on the front controller ll the
display begins to fl ash.
3. Use the UP or DOWN arrows to set to the current hour.
4. Press the SETTING bu on to confi rm and switch to minutes.
5. Use the UP or DOWN arrows to set the current minute.
6. Press the SETTING bu on to confi rm.
7
Simultaneously Press and Hold the TIME & SETTING bu ons on the front controller to exit this
mode.
OPERATION
Residen al Gas Water Heater Use and Care Guide • 53
Se ng Recircula on Mode and Recircula on Type
Table 20: Recircula on Mode Se ngs
Ac va ng the Recircula on Modes & Se ng the Aquasta c Parameters Built-in Controller
1 Press and hold the SETTING bu on to enter A mode.
2 Press the UP arrow to mode A05.
3 Press the SETTING bu on. The display will fl ash the current stored se ng.
4 Press the UP arrow to display 1.
5
Press the SETTING bu on to save the se ng. The display then will alternate between the
mode number and se ng.
6
Press the UP arrow to display A06 and/or A07 based on the recircula on mode and ac va on/
deac va on modes:
a. Set A06 to:
• Press SETTING, then press UP or DOWN to select the desired mode.
• 0 for Recircula on with a Return Line.
• 1 for Recircula on with a Crossover Valve.
• Press SETTING to save the selec on.
b. Set A07 to:
• Press the UP arrow to display A07
• Press SETTING, then press UP or DOWN to select the desired mode.
• 0 to ac vate the pump with the Pump Timers. Go to step 7.
• 1 to ac vate the pump with the On-Demand Push Bu on.
• Press SETTING to save the selec on. Go to step 19.
Steps 7-10 sets the standby me from the previous heater opera on, in minutes, ll the next
pump ac va on.
7 Press the DOWN bu on to go to mode A02.
8
Press the SETTING bu on to change the me delay se ng. Refer to Table 17 on page 51 for
available mes.
OPERATION
54 • Residen al Gas Tankless Water Heater Use and Care Guide
9 Press the UP or DOWN bu on to scroll to the desired me delay.
10
Press the SETTING bu on to save the se ng.
Go to the next step if the se ng in A06 is 0 (recircula on with a return line).
Go to step 19 if the se ng in A06 is 1 (crossover valve recircula on).
Steps 11-18 sets the inlet water temperatures to ac vate/deac vate the pump. These
values are subtracted from the water heater’s set temperature.
For example, with the default A03/A04 se ngs and set temperature of 120°F (49°C),
the pump will ac vate when the inlet water temperature goes below 100°F (38°C)
and deac vate when the inlet water temperature goes above 110°F (43°C).
11 Press the UP bu on to go to mode A03.
12
Press the SETTING bu on. The display will alternate between the mode number and
the current se ng.
13
Press the UP or DOWN bu on to select the desired se ng. Refer to Table 17 for
available se ngs.
14 Press the SETTING bu on to save the se ng.
15 Press the UP bu on to go to mode A04.
16
Press the SETTING bu on. The display will alternate between the mode number and
the current se ng.
17
Press the UP or DOWN bu on to select the desired se ng. Refer to Table 17 for
available se ngs.
18 Press the SETTING bu on to save the se ng.
19
Press and hold the SETTING bu on to exit the A mode. The display will return to the
set temperature.
OPERATION
Residen al Gas Water Heater Use and Care Guide • 55
Se ng the Pump Timers
Table 21: Se ng the pump mers
Se ng the Pump Timers Built-in Controller
1
Press and hold the TIME bu on. The display will fl ash the hour value for Pump Timer
1. The Pump Timer 1 symbol and ON will be displayed.
2 Press the UP or DOWN arrow to change the hour to the desired ac va on me.
3 Press the SETTING bu on to save the se ng and adjust the minute.
4
Press the UP or DOWN arrow to adjust minute. The ON se ng for Pump Timer 1
should now be set.
5 Press the SETTING bu on to save the se ng.
6
Press the PUMP bu on to switch to the OFF me for Pump Timer 1. The Pump Timer
1 symbol and OFF will be displayed below the me. Repeat steps 2-5 to set the off
me for Pump Timer 1.
7
Press the TIME bu on to switch to Pump Timer 2 and repeat steps 2-5 to set the ON
and OFF mes.
8 Press and hold the TIME bu on to exit.
MAINTENANCE
56 • Residen al Gas Tankless Water Heater Use and Care Guide 56 • Residen al Gas Tankless Water Heater Use and Care Guide
Pump Timer Ac va on
Table 22: Pump Timer Ac va on
Ac va ng the Pump Timers Built-in Controller
1 Display must be showing the set temperature.
2
Press and release the TIME bu on. The Pump Timer 1 LED will display a er
approximately 1 second. This will indicate that Pump Timer 1 is ac vated
3 Press and release the TIME bu on to ac vate only Pump Timer 2.
4 Press and release the TIME bu on to ac vate both Pump Timers.
5 Press and release the TIME bu on to turn off both Pump Timers.
MAINTENANCE
MAINTENANCE
Regular Maintenance
WARNING! Turn OFF the electrical
power supply and close the manual gas
shut-off valve and the manual water
control valve before servicing. Failure
to do so could result in serious personal
injury or death.
Rou ne maintenance will help your
water heater last longer and work
be er. Failure to perform required or
recommended maintenance may void
the warranty. If you cannot perform
these rou ne maintenance tasks
yourself, contact a qualifi ed person:
The manufacturer recommends having
the unit checked once a year or as
necessary by a licensed technician or
qualifi ed person. If repairs are needed,
any repairs should be done by a licensed
technician.
• Clean the cold-water/inlet fi lter.
• The intake and ven ng system should
be checked annually for any leaks,
corrosion, blockages, or damage.
Replace any damaged sec on of
ven ng and clear any blockage.
• Keep the area around the water heater
and termina ons clear. Regularly
ensure that the area around the water
heater, vent termina on, and air intake
is free from dust, debris, and other
contaminants. Remove any combus-
ble materials, gasoline, fl ammable
vapors, and liquids.
• If the pressure 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 situa on.
• The pressure relief valve must be
manually operated annually to check
for correct opera on. Before oper-
a ng the valve manually, check that
it will discharge in a place for secure
disposal.
• The condensate drain system must be
inspected regularly that it drains prop-
erly in accordance with local codes or
the manufacturer’s instruc ons.
• The screen on the rain protec on tray
should be inspected annually and
cleaned if needed.
Rain
Protection
Tray
Figure 43 - Rain Protec on tray
Freeze Protec on System
This unit comes equipped with hea ng
blocks as well as the auto-fi re mode to
protect it from damage associated with
freezing. The auto-fi re mode ac vates
the burner for a short period of me.
For this freeze protec on 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.
It is the installer’s responsibility
to be aware of freezing issues and
take all preventa ve measures. The
manufacturer will not be responsible for
any damage to the heat exchanger as a
result of freezing.
NOTICE: Only pipes within the water
heater are protected by the freeze
protec on system. Any water pipes (hot
or cold) located outside the unit will
not be protected. Properly protect and
insulate these pipes from freezing. See
“Available Accessories” on page 15 for
the Cartridge Freeze Protec on Kit. This
kit is availble for both the X3® Models
and M Models.
If you will not be using your heater for a
long period of me or power has been
lost during freezing condi ons:
1
Completely drain the water out
of the unit (see “Unit Draining
& Power Outage
(Freeze Protec on)” on page 58.
2
Disconnect power to your
water heater.
Residen al Gas Water Heater Use and Care Guide • 57
Unit Draining & Power
Outage
(Freeze Protec on)
1. Close the manual gas shutoff valve.
2. Disconnect power to the water heat-
er by unplugging it or by turning off
the circuit at the breaker box.
3. Close the cold inlet water valve.
4. Open all hot water taps in the house.
When the residual water fl ow has
ceased, close all hot water taps.
5. Drain the X3® (or Bypass)Cartridge:
Have a bucket or pan to catch water
from the X3® Cartridge. To remove
the X3® Cartridge, remove and keep
the 3 screws securing the cartridge
in place. Pull down to remove it from
the water heater. Empty the water
out of the cartridge into the bucket.
6. Wait a few minutes to ensure all
water has completely drained from
the unit.
7. Keep the cold water valve closed.
Keep the gas valve closed. Keep sup-
ply power disconnected.
8. To restore the unit to opera on rein-
stall the X3® Cartridge with 3 screws
removed earlier.
9. Open the cold inlet water valve.
Check all water connec ons for leaks.
If leaks are found, shut-off the cold
water inlet valve and immediately
fi x any leaks. If no leaks are present
proceed to the next step.
10. Reconnect power to the water heater.
11. Open the manual gas shutoff to the
water heater.
12. If the set temperature is not
displayed, press the ON/OFF bu on.
13. NOTE: If any errors occur shutoff the
water immediately.
Condensate Drain
• Inspect the drain lines for any clogs and
clear.
• Check the drain lines for a downward
slope. Correct any lines where water
does not drain freely.
• Inspect the built-in condensate trap
drain lines for debris. Disconnect the
lines and drain to remove the debris.
• If a neutralizer is installed, check the pH.
Replace the neutralizer if the pH of the
outlet water is below 6.0.
• If this fi lter is clogged, water will not be
supplied to the water heater properly.
Inlet Water Filter
1. Close the manual gas shutoff valve.
2. Disconnect power to the water heat-
er by unplugging it or by turning off
the circuit at the breaker box.
3. Close the inlet water valve.
4. Open all hot water taps in the house.
When the residual water fl ow has
ceased, close all hot water taps.
5. Drain the X3® (or Bypass)Cartridge:
Have a bucket or pan to catch water
from the X3® Cartridge. To remove
the X3® Cartridge, remove and keep
the 3 screws securing the cartridge
in place. Pull down to remove it from
the water heater. Empty the water
out of the cartridge into the bucket.
For detailed instruc ons see “X3®
Cartridge Removal” on page 40.
6. Wait a few minutes to ensure all
water has completely drained from
the unit.
7. Unscrew the inlet water fi lter and
remove it from the water heater.
8. Clean the fi lter: Check the water fi lter
located within the cold inlet. With a
ny brush, clean the water fi lter of
any debris which may have accumu-
lated.
9. Screw the inlet water fi lter back into
place. Hand- ghten only.
NOTICE: Handle with care and verify
the O-ring is not dirty or damaged.
10. To restore the unit to opera on rein-
stall the X3® Cartridge with 3 screws
removed earlier. For detailed instruc-
ons see “X3® Cartridge Installa on”
on page 40.
11. Turn ON the cold water supply to the
water heater at the cold inlet valve.
The system will fully pressurize and
any leaks at water connec ons will be
apparent. Correct any leaks immedi-
ately.
12. Turn ON the gas supply to the water
heater at the manual gas shut off
valve.
13. Restore power to the water heater.
The water heater is now ready for
opera on.
TROUBLESHOOTING
58 • Residen al Gas Water Heater Use and Care Guide
TROUBLESHOOTING
General Troubleshoo ng
Table 23: Troubleshoo ng Chart
PROBLEM SOLUTIONS
Temperature and Amount of Hot Water
It takes a long me to get
hot water at the fi xtures.
• The me it takes to deliver hot water from the water heater to your fi xtures depends on the length of
piping between the two. The longer the distance or the bigger the pipes, the longer it will take to get hot
water.
• If using the recircula on pump, check the se ngs to verify the Pump Timers are ac ve.
The water is not hot
enough.
• Check the set temperature of the water heater and adjust, if necessary.
• Check cross plumbing between the cold water lines and hot water lines.
• Is the gas supply valve open fully?
• Is the gas line sized properly?
• Is the gas supply pressure suffi cient?
• Check if the Point-of-Use mixing valves are set correctly, if they are installed.
The water is too hot. • Is the set temperature set too high?
The hot water is not
available when a fi xture
is opened.
• Make sure the unit has 120 VAC, 60 Hz power supply and power frequency is set to 60 hz.
• Verify the opera on se ng is ON by viewing the UIM. If the set temperature is showing or you press
the UP arrow to display the set temperature, then the opera on se ng is ON. If the display is blank and
nothing appears when pressing the UP bu on, then the opera on state is set to OFF. Press the ON/OFF
bu on to ac vate the heater. The set temperature will display when set to ON.
• Is the gas supply valve open fully and within the allowable gas pressure range?
• Is the water supply valve open fully?
• Is the fi lter on the cold water inlet clean?
• Is the hot water fi xture suffi ciently open to draw at least 0.4 GPM
(1.5 L/min) through the water heater?
• Is the unit frozen?
• Is there enough gas in the tank / cylinder? (For Propane models)
The hot water turns cold
and stays cold.
• Is the fl ow rate enough to keep the water heater running?
• If there is a recircula on system installed, does the recircula on line have
enough check valves?
• Is the gas supply valve open fully?
• Is the fi lter on the cold water inlet clean?
• Are the fi xtures clean of debris and obstruc ons?
Fluctua on in hot water
temperature.
• Is the fi lter on the cold water inlet clean?
• Is the gas line sized properly?
• Is the supply gas pressure suffi cient?
• Check for cross connec on between the cold water lines and hot water lines.
WATER HEATER
Unit does not ignite
when water goes
through the unit.
• Is the fl ow rate over 0.4 GPM (1.5 L/min)?
• Check for the fi lter on the cold water inlet.
• Check for reverse connec on and cross connec on.
• If you use the remote controller and/or built-in controller, is the power bu on
turned on?
• Check if the inlet temperature is too high. If it is too close to the set temperature,
the water heater will not ac vate.
The fan motor is s ll
spinning a er opera on
has stopped.
• This is normal. A er opera on has stopped, the fan motor keeps running
in order to re-ignite quickly, as well as purge all the
exhaust gas out of the fl ue.
Unit sounds abnormal
while in opera on
• Contact Technical Support Department.
Residen al Gas Water Heater Use and Care Guide • 59
Error Codes
The water heater has self-diagnos c func ons for safety and convenience when troubleshoo ng.
If there is a problem with the installa on or the unit, the error code associated with that failure will be displayed on the built-in controller or
remote controller. The display will fl ash E and the three digit number. It will show leading zeros. Example: E002
Error codes in the cascade system are diff erent. The heater number and E### (three digit number) will alternately fl ash on the parent unit’s
user interface module (UIM) and temperature remote controller. The child unit in error will fl ash the E### (three digit number) on it’s UIM.
Consult the the table below for the descrip on of each error code.
Fault Analysis of Error Codes
If the water heater is displaying an error code, please check the following. A er checking, consult with the manufacturer.
Table 24: Error Code Fault Analysis
Error
Code
Error Type Procedure
E002 Hi-Limit Switches
1. Manual Hi-Limit Switch on water outlet tripped. Check the switch for proper opera on.
Press the reset bu on (center of the switch), to reset it. NOTE: You will hear and feel the
switch click when rese ng it.
If the high limit switch con nues to trip contact a qualifi ed service technician.
2. Automa c Hi-Limit Switch on burner door tripped. If the automa c Hi-limit switch trip has
occurred, it cannot be reset and must be replaced. Contact a qualifi ed service technician.
E006 PCB Hardware Fault
1. Check PCB wiring for loose, damaged, or cut wires/connectors. Correct any loose con-
nec ons and replace any damaged wires/connectors. If all wires/connectors are intact,
replace the PCB.
E010 Frequency Fault
1. PCB has detected an incorrect power supply frequency. Note the default frequency is 60
Hz. Confi rm that C07 is set to the correct frequency of the supply power. See Table 18 to
access modes
2. If the se ng is correct and the error s ll occurs contact a qualifi ed service technician.
E011 PCB - Memory
1. The water heater will con nue to operate while in this error code is fl ashing, however,
the recircula on pump will be disabled. If this heater is part of a cascade system, then the
system will be aff ected based on the heater’s se ng.
• Parent Heater: The cascade system will not operate. Remove this heater from the cas-
cade system and set a diff erent heater as the Parent.
• Child Heater: This heater will not operate. The rest of the cascade system will con nue
to run.
E036 Flame Failure
WARNING! Working on an energized circuit can result in severe injury or death from
electrical shock.
1. Check the fl ame sensor wire for a short or disconnec on. Correct any loose connec ons
and replace any damaged wire/connector. If the error s ll occurs, contact a qualifi ed
service technician.
TROUBLESHOOTING
60 • Residen al Gas Water Heater Use and Care Guide
TROUBLESHOOTING
Error
Code
Error Type Procedure
E037 False Flame Detec on
WARNING! Working on an energized circuit can result in severe injury or death from
electrical shock.
1. Check for a visible fl ame through the sight glass while water is not running through the
water heater. If the error s ll occurs, immediately shut-off the water heater and contact a
qualifi ed service technician.
2. Check the fl ame sensor wire for a short or disconnec on. Correct any loose connec on
and replace any damaged wire/connector. If the error s ll occurs, contact a qualifi ed
service technician.
E038 Igni on Failure
WARNING! Working on an energized circuit can result in severe injury or death from
electrical shock.
1. Check for a visible fl ame through the sight glass.
2. Check the fl ame sensor wire and igniter wire for a short or disconnec on. Correct any
loose connec ons and replace any damaged wire/connector. If the error s ll occurs, con-
tact a qualifi ed service technician.
E041 Outlet Water Over-temp.
1. Verify the thermistor reading with the water outlet temperature.
2. Remove the outlet thermistor (do not lose the o-ring) and check for any dirt or debris.
Clean with an Emery cloth. If the thermistor is damaged, replace it. If the error s ll occurs,
contact a qualifi ed service technician.
E045 Clock Ba ery Replacement
1. The clock ba ery voltage is low indica ng it should be replaced with a 2032 type ba ery.
This error may also appear when supply power has been turned back on. In this case,
ignore the error code. Reference “Printed Circuit Board Ba ery” on page 42. Note: The
ba ery has a plas c cover, remove before installa on.40
E049 Exhaust Thermistor Failure
1. Remove the thermistor (do not lose the o-ring) and check for any dirt or debris. Clean
with an Emery cloth. If the thermistor is damaged, replace it.
2. Check the Thermistor sensor wire for a short or disconnec on. Correct any loose connec-
ons and replace any damaged wire/connector. If the error s ll occurs, contact a qualifi ed
service technician.
E050 Inlet Thermistor Failure
1. Remove the thermistor (do not lose the o-ring) and check for any dirt or debris. Clean
with an Emery cloth. If the thermistor is damaged, replace it.
2. Check the Thermistor sensor wire for a short or disconnec on. Correct any loose connec-
ons and replace any damaged wire/connector. If the error s ll occurs, contact a qualifi ed
service technician.
E051 Outlet Thermistor Failure
1. Remove the thermistor (do not lose the o-ring) and check for any dirt or debris clean with
Emery cloth. If the thermistor is damaged, replace it.
2. Check the Thermistor sensor wire for a short or disconnec on. Correct any loose connec-
ons and replace any damaged wire/connector. If the error s ll occurs, contact a qualifi ed
service technician.
E052
Heat Exchanger Thermistor
Failure
1. Remove the thermistor (do not lose the o-ring) and check for any dirt or debris clean with
Emery cloth. If the thermistor is damaged, replace it.
2. Check the Thermistor sensor wire for a short or disconnec on. Correct any loose connec-
ons and replace any damaged wire/connector. If the error s ll occurs, contact a qualifi ed
service technician.
Residen al Gas Water Heater Use and Care Guide • 61
TROUBLESHOOTING
Error
Code
Error Type Procedure
E383 Inlet Water Over-Temp.
1. Verify the inlet water temperature is not above the water heater’s set temperature.
2. Remove the inlet thermistor (do not lose the o-ring) and check for any dirt or debris.
Clean with Emery cloth. If the thermistor is damaged, replace it.
3. Check the Thermistor sensor wire for a short or disconnec on. Correct any loose connec-
ons and replace any damaged wire/connector. If the error s ll occurs. Contact a qualifi ed
service technician.
E384 False Flame Detec on
WARNING! Working on an energized circuit can result in severe injury or death from
electrical shock.
1. Look through the sight glass for a fl ame. If the fl ame is present, immediately shut off the
gas to the water heater. Contact a qualifi ed service technician before a emp ng to use
the water heater.
2. If no fl ame is present and the fl ame LED on the display is lit, Check the fl ame sensor wire
for a short or disconnec on. Correct any loose connec ons and replace any damaged
wire/connector. If the error s ll occurs, contact a qualifi ed service technician.
E385 Gas Valve - SV1
1. The PCB detects an incorrect voltage from the gas valve solenoid valve 1 (SV1). Correct
any loose connec ons and replace any damaged wire/connector. If the error s ll occurs,
contact a qualifi ed service technician to replace the gas valve.
E388 Bypass Valve
1. Correct any loose connec ons and replace any damaged wire/connector.
2. Follow the draining procedure on page 58 to properly drain the water heater. Remove
the Bypass valve and inspect for any debris or damage. Replace if needed.
E392 Fan - False Start
1. Check the fan motor wiring. Correct any loose connec ons and replace any damaged
wire/connector. If the error s ll occurs, contact a qualifi ed service technician.
E393 Fan - Signal Loss
1. Check the fan motor wiring. Correct any loose connec ons and replace any damaged
wire/connector. If the error s ll occurs, contact a qualifi ed service technician.
E394 Fan - Target Speed
1. Check the fan motor wiring. Correct any loose connec ons and replace any damaged
wire/connector.
2. With the water heater power disconnected, check the exhaust vent and air intake piping
for any blockages. Remove any blockages.
3. If the error s ll occurs, contact a qualifi ed service technician.
62 • Residen al Gas Water Heater Use and Care Guide
TROUBLESHOOTING
Error
Code
Error Type Procedure
E396 Pump - Low Speed
1. Check the pump wiring for a short or disconnec on. Correct any loose connec ons and
replace any damaged wire/connector.
2. Check the inlet fi lter for debris and clean.
3. Check the pump and water lines for debris and clear.
4. Check for a faulty check valve or something else crea ng resistance and clear.
5. Check to ensure the maximum pipe length and size has not been exceeded and meets the
requirements in the Recircula on and Combina on Potable Water sec ons of this manual.
6. If the error s ll occurs, contact a qualifi ed service technician.
E397 Pump - Low Current
1. Check the pump wiring for proper voltage.
2. If the error s ll occurs, contact a qualifi ed service technician.
E398 Pump - Low Water Flow
1. Check the pump wiring for a short or disconnec on. Correct any loose connec ons and
replace any damaged wire/connector.
2. Check the inlet fi lter for debris and clean.
3. Check the pump and water lines for debris and clear.
4. Check for a check valve stuck in the closed posi on; a shutoff valve in the closed posi on;
or something else crea ng resistance. Clear the blockage.
5. Check to ensure the maximum pipe length and size has not been exceeded and meets the
requirements in the Recircula on and Combina on Potable Water sec ons of this manual.
Table 13 on page 36.
6. If the error s ll occurs, contact a qualifi ed service technician.
E399 Pump - Power Limit Exceeded
1. Check the pump wiring for a short or disconnec on. Correct any loose connec ons and
replace any damaged wire/connector.
2. If the error s ll occurs,contact a qualifi ed service technician.
E400 Communica on Fault with UIM
1. Check the UIM wiring. Correct any loose connec ons and replace any damaged wire/
connector. If the error s ll occurs, contact a qualifi ed service technician.
E401
Communica on Fault with
Remote Controller
1. Check the Remote Controller wiring. Correct any loose connec ons and replace any dam-
aged wire/connector.
2. Only one remote controller can be installed, remove any addi onal remote controllers.
3. If the error s ll occurs, contact a qualifi ed service technician.
E402
Communica on Fault in
Cascade System
1. Check the Cascade wiring. Correct any loose connec ons and replace any damaged wire/
connector.
2. Cycle the heater’s power off /on if the cascade wiring was disconnected while the system
s ll had power.
3. If the error s ll occurs, contact a qualifi ed service technician.
Residen al Gas Water Heater Use and Care Guide • 63
64 • Residen al Gas Water Heater Use and Care Guide
TROUBLESHOOTING
Error
Code
Error Type Procedure
E403 Fan - Low Speed
1. Check the fan motor wiring. Correct any loose connec ons and replace any damaged
wire/connector.
2. With the water heater power disconnected, check the exhaust vent and air intake piping
for any blockages. Remove any blockages.
3. If the error s ll occurs, contact a qualifi ed service technician.
E411
Heat Exchanger - Water
Overhea ng.
1. Remove the heat exchanger thermistor (do not lose the o-ring) and check for any dirt or
debris. Clean with an emery cloth. If the thermistor is damaged, replace it.
2. Check the Thermistor sensor wire for a short or disconnec on. Correct any loose connec-
ons and replace any damaged wire/connector. If the error s ll occurs, contact a qualifi ed
service technician.
E412 PCB - Hardware
1. Contact a qualifi ed service technician to replace the PCB.
E413 Flame Sensor
1. Check the fl ame sensor wire for a short or disconnec on. Correct any loose connec ons
and replace any damaged wire/connector.
2. With the water heater power disconnected, check the exhaust vent and air intake piping
for any blockages. Remove any blockages.
3. Verify the water heater has suffi cient combus on air, reference the Combus on and Vent-
ing Installa on sec on in the manual.
4. Check the installa on area for corrosive elements, reference the see Installa on
Environment sec on in the manual.
5. If the error s ll occurs, contact a qualifi ed service technician.
E414 PCB-Flame Sensor Circuit
1. Check the fl ame sensor wire for a short or disconnec on. Correct any loose connec ons
and replace any damaged wire/connector.
2. If the error s ll occurs, contact a qualifi ed service technician to replace the PCB.
E415 Gas Valve Fault
1. Check the gas valve wiring for a short or disconnec on. Correct any loose connec ons and
replace any damaged wire/connector.
2. If the error s ll occurs, contact a qualifi ed service technician.
E416 Analog/Digital (AD) Value Fault
1. Check the outlet thermistor sensor wire for a short or disconnec on. Correct any loose
connec ons and replace any damaged wire/connector. If the error s ll occurs, contact a
qualifi ed service technician.
2. Remove the outlet thermistor (do not lose the o-ring) and check for any dirt or debris.
Clean with an Emery cloth. If the thermistor is damaged, replace it.
3. If the error s ll occurs, contact a qualifi ed service technician to replace the PCB.
Residen al Gas Water Heater Use and Care Guide • 65
TROUBLESHOOTING
Error
Code
Error Type Procedure
E417 Flame Sensor Fault
1. Check the fl ame sensor wire for a short or disconnec on. Correct any loose connec ons
and replace any damaged wire/connector.
2. Check the inlet & heat exchanger thermistor sensor wires for a short or disconnec on.
Correct any loose connec ons and replace any damaged wire/connector.
3. Remove the inlet & heat exchanger thermistors (do not lose the o-ring) and check for any
dirt or debris. Clean with an Emery cloth. If the either thermistor is damaged, replace it.
E418 Exhaust High Temperature
1. With the water heater power disconnected, check the exhaust vent and air intake piping
for any blockages. Remove any blockages.
2. Remove the exhaust thermistor (do not lose the o-ring) and check for any dirt or debris
clean with Emery cloth. If the thermistor is damaged, replace it.
3. If the error s ll occurs, contact a qualifi ed service technician.
E420 Gas Valve - SV2
1. PCB detects an incorrect voltage from the gas valve’s SV2. Correct any loose connec ons
and replace any damaged wire/connector. If the error s ll occurs contact a qualifi ed ser-
vice technician to replace the gas valve.
E421 Pressure Switch
1. Check the pressure switch wires for a short or disconnec on. Correct any loose connec-
ons and replace any damaged wire/connector.
2. Check the pressure tube for loose connec ons, debris, or blockages. Correct any issue
immediately.
3. With the water heater power disconnected, check the exhaust vent and air intake piping
for any blockages. Remove any blockages.
4. If the error s ll occurs, contact a qualifi ed service technician.
E422 Venturi Assembly
1. Check the venturi assembly wires for a short or disconnec on. Correct any loose connec-
ons and replace any damaged wire/connector.
2. If the error s ll occurs, contact a qualifi ed service technician.
E426 Condensate Drain Overfl ow
1. Place a bucket under the water heater to catch any water.
2. With the water heater off , check the condensate drain for any blockages. Remove any
blockages.
3. With the water heater off , check the condensate trap for any blockages. Remove any
blockages.
4. Check the condensate drain wires for a short or disconnec on. Correct any loose connec-
ons and replace any damaged wire/connector.
5. Verify the condensate drain line is installed correctly, reference “Condensate Drain” on
page 41.
E427 Flow Control Valve
1. Check the fl ow control valve wires for a short or disconnec on. Correct any loose connec-
ons and replace any damaged wire/connector.
2. Remove the fl ow control valve and inspect for any debris or damage. Replace if needed.
First follow the draining procedure in the Unit Draining & Power Outage sec on in this
manual.
66 • Residen al Gas Water Heater Use and Care Guide
TROUBLESHOOTING
Error
Code
Error Type Procedure
E428 Flow Sensor - Cascade Only
1. Verify the water heater’s opera on is enabled. The heater’s UIM will display the set tem-
perature when enabled. If it is disabled, press the heater’s ON/OFF bu on to enable the
heater’s opera on.
2. Verify that the heater’s water shutoff valves are open.
3. Check the fl ow sensor wires for a short or disconnec on. Correct any loose connec ons
and replace any damaged wire/connector.
4. Drain the water heater following Unit Draining & Power Outage sec on in this manual.
5. Remove the fl ow sensor and inspect for any debris or damage. Replace if needed.
6. Remove and clean the inlet water fi lter.
E429
Flow Control Valve Fault -
Cascade Only.
1. Check the fl ow control valve wires for a short or disconnec on. Correct any loose connec-
ons and replace any damaged wire/connector.
2. Remove the fl ow control valve and inspect for any debris or damage. Replace if needed.
First follow the draining procedure in the Unit Draining & Power Outage sec on in this
manual.
Residen al Gas Water Heater Use and Care Guide • 67
COMPONENT LIST
1
18
22
3
20
4
6
21
28
14
25
13
2
7
12
34
68 • Residen al Gas Tankless Water Heater Use and Care Guide
COMPONENT LIST
18
22
3
5
6
4
28
20
14
27
12
10
24
26
21
16
8
9
15
19
7
Residen al Gas Tankless Water Heater Use and Care Guide • 69
COMPONENT LIST
18
3
5
6
20
14
7
12
10
23
21
16
22
15
24
29
17
32
31
30
33
COMPONENT LIST
70 • Residen al Gas Tankless Water Heater Use and Care Guide
COMPONENT LIST
Residen al Gas Tankless Water Heater Use and Care Guide • 71
COMPONENT LIST
When ordering repair parts, always give the following informa on:
1. Model and serial numbers. This info should be on the le side of the water heater
2. Part(s) descrip on
Item
No.
Component List
1 AIR PRESSURE SWITCH
2 CONDENSATE TRAP
3 BURNER DOOR HI-LIMIT
4 FLAME SENSOR
5 HEAT EXCHANGER THERMISTOR
6 HI-LIMIT SWITCH (MANUAL RESET)
7 GAS VALVE
8 USER INTERFACE
9 PRINTED CIRCUIT BOARD
10 INLET FILTER
11 BYPASS CARTRIDGE (NOT SHOWN)
12 X3® CARTRIDGE
13 OUTLET WATER TUBE
14 BYPASS WATER TUBE
15 HEAT EXCHANGER OUTLET WATER TUBE
16 INLET WATER TUBE
17 CASE (FRONT COVER NOT SHOWN FOR CLARITY)
18 EXHAUST THERMISTOR
19 IGNITER RODS
20 BURNER ASSEMBLY
21 FAN
22 IGNITER
23 PUMP
24 FLOW SENSOR/FLOW CONTROL VALVE ASSEMBLY
25 BYPASS VALVE
26 INLET THERMISTOR
27 OUTLET THERMISTOR
28 VENTURI ASSEMBLY
29 CASE FRONT COVER
30 MOUNTING BRACKETS
31 EXHAUST PORT
32 INLET PORT
33 OUTDOOR VENT CAP
34 HEAT EXCHANGER ASSEMBLY
72 • Residen al Gas Tankless Water Heater Use and Care Guide
FLOW RATE
Flow Rate Capacity Chart
The chart is based on a properly sized gas line and installa on at 0-2,000 . (0-610 m). The water heater will de-rate approximately 3% (NG) or 4.5%
(LP) per 1,000 . (305 m) of eleva on increase above 2,000 . (610 m).
0
1
2
3
4
5
6
7
8
9
10
11
12
30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Flow Rate (GPM)
THR Flow Rate Capacity Chart
THR-160 THR-180 THR-199
Temperature Rise (°F)
Residen al Gas Tankless Water Heater Use and Care Guide • 73
Copyright © 2024, A. O. Smith.
All Rights Reserved
