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.
Residen al Gas
Tankless Water Heater
Residen al On-Demand Gas Tankless Water Heater
(X3™ TECHNOLOGY available on some models)
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.
MODEL:
THR-160, THR-180, THR-199
LOW LEAD
C
O
NTENT
100374994_2000628591
December 2023
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 INSTALLATION (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 and VenƟ ng InstallaƟ on ......................................................................................................18
VenƟ ng ....................................................................................................................................................21
Installing the Vent Pipe. ..........................................................................................................................23
Exhaust Vent for Indoor InstallaƟ on ........................................................................................................23
Clearances for Sidewall TerminaƟ ons .....................................................................................................28
Clearances for RooŌ op TerminaƟ ons ......................................................................................................29
Exhaust VenƟ ng for Outdoor InstallaƟ on ................................................................................................30
Outdoor Available Accessories ................................................................................................................30
Gas Conversion InstrucƟ ons ....................................................................................................................33
Water ConnecƟ ons ..................................................................................................................................33
RecirculaƟ on ...........................................................................................................................................34
CombinaƟ on Potable Water HeaƟ ng ......................................................................................................36
Residen al Gas Tankless Water Heater Use and Care Guide • 3
TABLE OF CONTENTS
Dual Purpose Water HeaƟ ng for the State of MassachuseƩ s .................................................................37
X3® Technology .......................................................................................................................................38
Pressure Relief Valve ...............................................................................................................................38
Electrical ConnecƟ ons .............................................................................................................................40
Cascade System .......................................................................................................................................41
OPERATION ...................................................................................................43
FOR YOUR SAFETY, READ BEFORE OPERATING ........................................................................................ 43
Temperature Adjustment ........................................................................................................................46
Unit Conversion Mode .............................................................................................................................47
Confi guraƟ on Mode (A Mode) ................................................................................................................48
Confi guraƟ on Mode (C Mode) ................................................................................................................48
Seƫ ng the Clock .....................................................................................................................................49
Seƫ ng RecirculaƟ on Modes....................................................................................................................50
Seƫ ng the Pump Timers .........................................................................................................................52
Pump Timer AcƟ vaƟ on ............................................................................................................................53
MAINTENANCE .............................................................................................. 54
Regular Maintenance ..............................................................................................................................54
Unit Draining & Power Outage
(Freeze ProtecƟ on) .................................................................................................................................55
Condensate Drain ....................................................................................................................................55
TROUBLESHOOTING .....................................................................................56
General TroubleshooƟ ng .........................................................................................................................56
Error Codes ..............................................................................................................................................57
Fault Analysis of Error Codes ...................................................................................................................57
COMPONENT LIST ..........................................................................................63
FLOW RATE ....................................................................................................70
NOTES ...........................................................................................................71
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. 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
Tank
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.
WATER HEATER BASICS
TYPICAL INSTALLATION (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 ME
ASUREMENT CONNECTION SIZE
1 HOT OUTLET 9.00 in/23 cm 3/4” MNPT
2
GAS INLET 6.90 in/17.52 cm 1/2” MNPT
3 CONDENSATE 3.20 in/8.07 cm 1/2” MNPT
4 COLD INLET 4.80 in/12.20 cm 3/4” MNPT
WALL
1
2
3
4
SUPPLY CONNECTIONS
8 • Residen al Gas Tankless Water Heater Use and Care Guide
X3® Models: Comes 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" NPT
Water Connections 3/4" 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
" W.C. (kPa)
Min 3.5 (0.87)
Max. 10.5 (2.62)
Propane
Inlet Pressure
" 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 120V, 50Hz/60Hz, <5A
Water Heater Category** Category IV
Maximum Pipe length
(Hot Water supply line and Dedicated
Return line)
Pipe
Diameter
3/4" 500 ft (152.4 m)
1/2" 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 Pressure
Relief Valve Maintenance section of this
manual.
See the 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 manu-
facturer of the Pressure Relief Valve
(label a ached to Pressure Relief
Valve). If no label is a ached to the
Pressure Relief Valve, follow the
instruc ons in the Pressure Relief
Valve Maintenance sec on of this
manual. An explosion could occur if
the Pressure Relief Valve or dis-
charge pipe is blocked. Do not cap
or plug the Pressure Relief Valve or
discharge pipe.
Gas Pressure
WARNING! The gas supply
pressure must not exceed the
maximum supply pressure as stated
on the water heater’s data plate. The
minimum supply pressure is for the
purpose of input adjustment. L.P.
gas supply pressure must not exceed
14” water column. Have a qualifi ed
person (licensed plumber, gas
company personnel, or authorized
service technician) check for proper
L.P. gas pressure. L.P. gas pressures
exceeding 14” water column 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 show-
ering.
• To reduce the risk of scalding, install
Thermosta c Mixing Valves (tem-
perature limi ng valves) at each
point-of-use. These valves automa -
cally mix hot and cold water to limit
the temperature at the tap. Mixing
valves are available at your local
plumbing supplier. Follow the man-
ufacturer’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,
Thermosta 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.
Even if you set the water heater’s gas
control valve to a low se ng, higher
water temperatures may occur in
certain circumstances.
• Water temperature will be ho er if
someone adjusted the set tempera-
ture to a higher se ng.
• Should overhea ng occur or the
burner fail to shut 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 im-
mersed 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
absence of local codes, follow the
current edi on of ANSI Z223.1/NFPA
54, Na onal Fuel Gas Code in the
USA or B149.1, Natural gas and pro-
pane 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 Stan-
dard, Title 24 CFR, Part 3280 and/or
CSA Z240 MH Series, Manufactured
Homes.
• Follow the electrical code require-
ments of the local authority having
jurisdic on. In the absence of such
requirements, 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
“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. Consider 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. 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. If
you install a drain pan under the
unit, ensure that it will not restrict
the combus on air fl ow.
• 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) min-
imum clearance from the le and
right sides of the unit.
• The manufacturer does not recom-
mend installing the water heater
in an a c due to safety issues. See
the installation section for further
information.
GETTING STARTED
Residen al Gas Tankless Water Heater Use and Care Guide • 13
GETTING STARTED
• Failure to observe these warnings
could result in severe personal injury,
death, and/or property damage.
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 ex-
haust vent is poin ng into any open-
ing 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 an inside corner
for both outdoor installa on and
direct-vent installa on.
Outside
corner
Inside
corner
3
min.
2
min.
2
min.
Overhang
Figure 1 - Over hang and Inside Corner
Restric ons
• Do not install next to a dryer or any
source of airborne debris that can be
trapped inside the combus on cham-
ber, unless the system is direct-vent-
ed. 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.
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Figure 2 - Minimum Vent Clearances (Indoor)
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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 appro-
priate for the type of water pipes in
your home.
• Thread sealant tape or pipe joint
compound approved for potable
water.
• For homes with water lines using
threaded connectors suitable for the
specifi c type of plas c pipe used:
CPVC or PEX (cross-linked polyeth-
ylene). 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” x 3” 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” x 3/8” Vent Screw (x2)
X3® Cartridge
Screws
(x1)
(x2)
Screws to secure the X3® Cartridge
• M4-12mm (1x)
• M4-25mm (2x)
Cascading Cable
Cascading Cable for electronically connec ng tankless water heaters in
series for greater output.
• P/N 100371915
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” 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” 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 . (3m) cable.
• P/N 100371898
Communica on
Cables
Communica on Cable Extensions for Remote Temperature Controller, Wi-Fi
Module, or On-Demand Receiver.
• P/N 100371899 for 10 . (3 m)
• P/N 100371900 for 32 . (10 m)
Remote
Recircula on Kit
Remote Recircula on Kit engages heater and recircula on at a touch of a
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 100371913
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 secondary 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
• 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 Tee 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 54.
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 data plate, located next to
the gas control valve/thermostat.
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
Total
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 recommend-
ed); 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 volume 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 % 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 small-
er than 100 square inches.
• Ducts must have the same cross-sec-
onal area as free area of the
opening.
• Rectangular ducts must have a
minimum dimension of no less than
three inches.
• All screens must have mesh ¼” or
larger.
• Movable louvers must be locked
open or interconnected with the
equipment so that they open auto-
ma 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/h
/ŶůĞƚĂŝƌĨƌŽŵ
ƚŚĞĐƌĂǁůƐƉĂĐĞ
KƉĞŶĨŽƵŶĚĂƟŽŶǀĞŶƚ
ŽŶĮŶĞĚ
^ƉĂĐĞ
Alternate
Air Inlet
ϭŝŶ
2
;ϲϱĐŵ
2
)
p
er 4,000 btu/h
Figure 9 - Direct to Outdoors Openings
Two permanent
Openings
1 in
2
(6.5 cm
2
)
per 4,000 btu/h
12” (305 mm)
maximum
12” (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/h
/ŶůĞƚĂŝƌĚƵĐƚ
ϭŝŶ
2
;ϲϱĐŵ
2
)
per 4,000 btu/h
ŽŶĮŶĞĚ
^ƉĂĐĞ
ϭϮ;ϯϬϱŵŵͿ
ŵĂdžŝŵƵŵ
'ĂďůĞǀĞŶƚ
ƚŽŽƵƚĚŽŽƌƐ
/ŶƐƚĂůůĂďŽǀĞ
ŝŶƐƵůĂƟŽŶ
Figure 11 - Ver cal Duct Openings
1 in
2
(6.5 cm
2
)
per 2,000 btu/h
ŽŶĮŶĞĚ
Space
Outlet
Inlet
KƵƚĚŽŽƌ
Air Ducts
1 in
2
(6.5 cm
2
)
per 2,000 btu/h
Figure 12 - Horizontal Duct Openings
ŽŶĮŶĞĚ
^ƉĂĐĞ
1 in
2
(6.5 cm
2
)
ƉĞƌϯϬϬϬbtu/h
ůƚĞƌŶĂƟǀĞ
KƉĞŶŝŶŐ
>ŽĐĂƟŽŶ
Figure 13 - Single Opening
Two permanent
Openings
1 in
2
per
1,000 btu/h
12” (305 mm)
maximum
12” (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
instruc ons when installing the vent
pipe.
• Place the water heater as close as
possible to the vent termina on.
• The vent collar of the water heat-
er 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
common vented to any other gas
appliance or vent stack.
• Air supply pipe can be made of ABS,
PVC (solid core), CPVC (solid core),
polypropylene, or Category lll/IV
stainless steel.
• Use of cellular core PVC (ASTM
F891), cellular core CPVC, or Radel®
(polyphenylsulfone) in nonmetallic
ven ng systems is prohibited
• Covering non-metallic vent pipe and
fi ngs with thermal insula on is
prohibited.
• Sidewall ven ng is recommended
for the Indoor model. Ver cal vent-
ing (roof termina on) is acceptable.
• The manufacturer recommends run-
ning 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 pre-
vents rain water from entering into
the water heater must be installed.
• Do not terminate vent into a chim-
ney. 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 termina on be at least 12 in
(305 mm) above grade and an ci-
pated snow level, but the installer
may determine 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" ven ng 3" 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
exhaust/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" straight pipe fully
into the exhaust/intake ports.
(See Figure 15) The pipes
should insert 2 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” Ven ng, install a 2” x
3” increaser to convert to 3” ven ng.
For low clearance installa ons, a 2”
long sweep elbow may be used. Then
1 max length straight pipe may be
used to fi t a 2” x 3” increaser.
Air Intake for Power Vent Installs:
Insert the male end of a 2” or 3” 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” Pipe
2” to 3”
Adapter
2” Pipe
2” Pipe
3” Pipe
2” to 3”
Adapter
2” Pipe
2” Pipe
2” Pipe
2” 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 and intake piping shall not
exceed the lengths listed in Table 8.
• Do not use more than 5 elbows in a
vent system. 90 degree elbow add-
ed, deduct 5 . 45 degree elbows
count as 2.5 feet. 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 neces-
sary.
• Slope horizontal ven ng sec ons
1/4" upwards for every 12" (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 on-
al Fuel Gas Code or B149.1, Natural
gas and propane installa on code.
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 Installa on Example
Horizontal Installation
Hanger
Roof
flashing
Fire stop
Vertical Installation
Figure 16 - Vent Confi gura ons for Direct Vent
Power Vent Installa on Examples
Horizontal Installation
Hanger
Vertical Installation
Roof
flashing
Fire stop
Figure 17 - Vent Confi gura ons for Power Vent
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" 100187903 196984 397984
3" 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" 100112869 196005 397005 197040
3" 100112163 196006 397006 197006
POLYPROPYLENE CONCENTRIC TERMINATION
Vent Pipe Size Centrotherm Part Number
2" ISLPT0202
3" ISLPT0303
26 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
POLYPROPYLENE TERMINATION TEE
Vent Pipe Size Centrotherm Part Number
2" ISTT0220
3" ISTT0320
POLYPROPYLENE RADIUS ELBOWS
Vent Pipe Size Centrotherm Part Number
2" 45° EXHAUST ELBOW ISELS0245UV
3" 45° EXHAUST ELBOW ISELS0345UV
2" 87° INLET ELBOW ISELS0287UV
3" 87° INLET ELBOW ISELS0387UV
POLYPROPYLENE CONCENTRIC WALL TERMINATION
Vent Pipe Size Centrotherm Part Number
2" ICWT242
3" ICWT352
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 dam-
age; 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 feet (610
mm) from an inside corner
ŶƟĐŝƉĂƚĞĚ^ŶŽǁůĞǀĞů
džŚĂƵƐƚ
dĞƌŵŝŶĂƟŽŶ
ϮŌ
;ϲϭϬŵŵͿ
ŵŝŶ
ϭŌ
;ϯϬϱŵŵͿ
ŵŝŶ
;ϯϬϱŵŵͿ
ŵŝŶ
/ŶƐŝĚĞ
ĐŽƌŶĞƌ
Figure 18 - 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 termi-
na 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 19 - 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 20 - 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 21 - Direct Vent Sidewall Termina ons
Residen al Gas Tankless Water Heater Use and Care Guide • 29
INSTALLATION
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 horizontal 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.
ŶƟĐŝƉĂƚĞĚƐŶŽǁůĞǀĞů
ϮŌ;ϲϭϬŵŵͿŵŝŶ
ϭŌ
;ϯϬϱŵŵͿ
ŵŝŶ
ϭŌ
;ϯϬϱŵŵͿ
ŵŝŶ
ϭŌ
;ϯϬϱŵŵͿ
ŵŝŶ
Figure 22 - Angled Roof Termina on
Figure 23 - Flat Roof Termina on
(305 mm)
min.
(305 mm)
min.
(914 mm)
min.
(305 mm)
min.
(305 mm)
min.
(610 mm)
min.
(305 mm)
min.
Figure 24 - Mul ple Angled Roof Termina ons
Figure 25 - Mul ple Flat Roof Termina on
30 • 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
rotate the printed circuit
board down.
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 40.
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 40.
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 • 31
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 complet-
ed 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” W.C. (0.87 kPa)
Max. 10.5“ W.C. (2.62 kPa)
Propane:
Min 8.0” W.C. (1.99 kPa)
Max. 13.0” 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 pres-
sures are measured when the water
heater and any other gas appliance
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 con-
di 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 regula-
tor 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 manufacturers 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
water heater's minimum to maxi-
mum input and provide the speci-
fi ed pressures that are listed on the
ra ng plate.
• In the absence of minimum install
distance stated by the regulator
manufacturer, 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" union to connect
gas piping to the water
heater's 1/2" 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 iso-
lated 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.
32 • 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" 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'
(3.0 m)
20'
(6.1 m)
30'
(9.1 m)
40'
(12.2 m)
50'
(15.2 m)
60'
(18.3 m)
70'
(21.3 m)
80'
(24.4 m)
90'
(27.4 m)
100'
(30.5 m)
125'
(38.1 m)
150'
(45.7 m)
200'
(61.0 m)
1/2" 172
118 95 81 72 65 60 56 52 50 44 40 34
3/4" 360 247 199 170 151 137 126 117 110 104 92 83 71
1" 678 466 374 320 284 257 237 220 207 195 173 157 134
1-1/4" 1,390 957 768 657 583 528 486 452 424 400 355 322 275
1-1/2" 2,090 1,430 1,150 985 873 791 728 677 635 600 532 482 412
2" 4,020 2,760 2,220 1,900 1,680 1,520 1,400 1,300 1,220 1,160 1,020 928 794
Propane (LP) supply piping
Maximum Capacity of Propane (LP) Based on 11" W.C. supply pressure at a 0.5" W.C. pressure drop. (Unit: kBTU per hour)
Table 12: Propane Gas Table
Pipe Size Length
Diameter
10'
(3.0 m)
20'
(6.1 m)
30'
(9.1 m)
40'
(12.2 m)
50'
(15.2 m)
60'
(18.3 m)
70'
(21.3 m)
80'
(24.4 m)
90'
(27.4 m)
100'
(30.5 m)
125'
(38.1 m)
150'
(45.7 m)
200'
(61.0 m)
1/2"
268
184 148 126 112 101 93 87 82 77 68 62 53
3/4" 567 393 315 267 237 217 196 185 173 162 146 132 112
1" 1,071 732 590 504 448 409 378 346 322 307 275 252 213
1-1/4" 2,205 1,496 1,212 1,039 913 834 771 724 677 630 567 511 440
1-1/2" 3,307 2,299 1,858 1,559 1,417 1,275 1,181 1,086 1,023 976 866 787 675
2" 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/Cubic :
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 cubic per hour requirement of 220 cubic 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
order to supply 220 cubic .
Residen al Gas Tankless Water Heater Use and Care Guide • 33
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 installed.
• 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 di-
electric-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 com-
plete, 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 en-
tering 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
water heater’s connec ons (using
thread sealant tape or pipe joint
compound). Connect the home’s
water pipes by soldering, keeping
the connec ons at the water heater
cool with wet rags.
34 • 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
California’s Title 24
Details of the opera on are listed
below. In each mode, the heater’s
pump only operates when there is not
any demand from the home’s fi xtures.
The water heater will stop the pump
if there is a demand from one of the
home’s fi xtures.
• 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 confi gure 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 52 to set the
Pump Timers.
• Crossover Valve Mode - In this
mode, a “crossover” valve is typical-
ly 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 manufacturer.
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 tempera-
ture on the hot side drops below
95°F (35°C) and will close when the
temperature reaches 105°F (40.5°C).
NOTICE: These temperature values
may vary from manufacturer to
manufacturer. Refer to Tables 20
and 21 to set the Crossover Valve
Recircula on mode and the Pump
Timers. For manufacturer recom-
mended crossover valve see “Avail-
able Accessories” on page 15.
NOTICE: Func on/compa bilty 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" 500 ft (152.4 m)
1/2" 200 ft (61 m)
NOTE: These are equivalent length
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 approxi-
mately 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 con nuously will
reduce the warranty of the water
heater.
• An air elimina on device is suggest-
ed to remove air from the piping
system. Air may cause the recircu-
la on pump to cavitate and may
reduce the water fl ow rate. These
Residen al Gas Water Heater Use and Care Guide • 35
INSTALLATION
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
36 • 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 chemicals were added to the
water hea ng appliances.
• Toxic chemicals used in boiler
treatments such as alcohol, glycer-
ol, 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
pressure 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
SUPPLYCHECK
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 • 37
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
absence 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
Figure 32 - Diagramma c Layout of Radiant Hea ng and Domes c Water Heater
38 • 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
1
screws fi rst and lastly
ghten screw
2
. DO NOT use a
drill or impact driver to ghten the
screws.
2 11
21
1
2
1
1
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 screw 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.
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.
Residen al Gas Water Heater Use and Care Guide • 39
INSTALLATION
Refer to the pressure relief valve
manufacturer's instruc ons for
inspec on and maintenance
requirements.
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
approved pressure relief valve shall
be fi eld supplied for the M models.
• The discharge piping for the pres-
sure relief valve must be directed
so that the hot water cannot splash
outward and cause damage or per-
sonal injury.
• A ach the discharge tube to the
pressure relief valve and run the end
of the tube to within 6 in (152 mm)
from the fl oor. This discharge tube
must allow free and complete drain-
age without any restric ons.
• If the pressure relief valve discharg-
es 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 periodically 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 neu-
tralizers 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” corrosion
resistant pipe, such as PVC, for the
condensate 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
Battery
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.
• This water heater can be
confi gured to run on 120 VAC 50
Hz. See Table 18 on page 48 to
change this se ng.
3
The water heater can be
hardwired or wired to a plug-in.
4
The use of a surge protector
is recommended in order to
protect the unit from power
surges.
Indoor model
1
The water heater should be
plugged into a 120VAC, 60 HZ
electrical outlet.
Outdoor model
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.
40 • Residen al Gas Tankless Water Heater Use and Care Guide
INSTALLATION
Residen al Gas Tankless Water Heater Use and Care Guide • 41
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.
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 the
first water heater connected to the
cold water supply and 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 cover(s)
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
buttons until C00 appears.
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
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.
42 • Residen al Gas Water Heater Use and Care Guide
INSTALLATION
Parent UnitChild UnitChild UnitChild Unit
CWS
HWS
Gas
Supply
Building Return
Cascade
Linking
Cable
Parent UnitChild Unit
Single
Harness
End
Child Unit
hild Unit
Double
Harness
End
Figure 39 - Mul Unit Cascade Confi gura on
Residen al Gas Water Heater Use and Care Guide • 43
OPERATION
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 31.
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.
NOTICE: Some unit may be
hardwired.
3
The user interface will display
the current temperature set-
ting. 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” on page
46.
Shut-Down Instruc ons
1
Press the “ON/OFF” button
and wait for the water heater
to shut-off.
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
Turn off all electrical power
to the water heater. (Unplug
it from the 120 VAC outlet.)
4
Call a qualifi ed person
(licensed plumber, authorized
gas company personnel, or
authorized service technician for
assistance.
Figure 40 - Ligh ng Instruc ons
44 • Residen al Gas Tankless Water Heater Use and Care Guide
OPERATION
Residen al Gas Tankless Water Heater Use and Care Guide • 45
OPERATION
1 2
ON OFF
PM
AM
A
B
C
D
E
F
G
H
I
J
K
L
M
Figure 41 - 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
46 • Residen al Gas Tankless Water Heater Use and Care Guide
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 T
urn 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 sec-
onds 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.
Residen al Gas Tankless Water Heater Use and Care Guide • 47
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. T
urn 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.
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).
48 • Residen al Gas Tankless Water Heater Use and Care Guide
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 Timer
°F
°C
-10 -15 -20 (default) -25 -30 -35 -40
-6 -8 -11 (default) -14 -17 -19 -22
A04 Pump Turn Off Timer
°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 CT24 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.
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:
50:
60Hz (default)
50Hz
OPERATION
Residen al Gas Water Heater Use and Care Guide • 49
CODE DESCRIPTION OPTIONS
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 Descale 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. T
urn 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
50 • Residen al Gas Tankless Water Heater Use and Care Guide
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
48 for available mes.
OPERATION
Residen al Gas Water Heater Use and Care Guide • 51
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
52 • Residen al Gas Tankless Water Heater Use and Care Guide 52 • Residen al Gas Tankless Water Heater Use and Care Guide
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.
OPERATION
Pump Timer Ac va on
Table 22: Pump Timer Ac va on
Ac va ng the Pump Timers Built-in Controller
1 Displa
y 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.
Residen al Gas Tankless Water Heater Use and Care Guide • 53
OPERATION
54 • Residen al Gas Tankless Water Heater Use and Care Guide
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. 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. Reg-
ularly 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 materi-
als, 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 periodically to
check for correct opera on. Before
opera 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 properly 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 42 - Rain Protec on tray
Freeze Protec on System
This unit comes equipped with
hea ng blocks and will auto-fi re 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 55
2
Disconnect power to your
water heater.
Residen al Gas Tankless Water Heater Use and Care Guide • 55
Unit Draining & Power
Outage
(Freeze Protec on)
1. Close the manual gas shutoff
valve.
2. Disconnect power to the wa-
ter heater 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
supply power disconnected.
8. To restore the unit to opera on
reinstall 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 down-
ward slope. Correct any lines where
water does not drain freely.
• Inspect and clear any debris in the
built-in condensate trap. Remove
the ball trap assembly.
• If a neutralizer is installed, check the
pH. Replace the neutralizer if the pH
of the outlet water is below 6.0.
MAINTENANCE
56 • Residen al Gas Tankless 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.
• 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 Tankless Water Heater Use and Care Guide • 57
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 UIM. 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
connec 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 fre-
quency 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 cas-
cade 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 cascade 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
58 • Residen al Gas Tankless Water Heater Use and Care Guide
TROUBLESHOOTING
Error
Code
Error Type Procedure
E037 False Flame Detec on
W
ARNING! 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 con-
nec 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. Cor-
rect any loose connec ons and replace any damaged wire/connector. If the error
s ll occurs, contact a qualifi ed service technician.
E041 Outlet Water Over-temp.
1. Verify the thermistor reading with the water outlet temperature.
2. 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. 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 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 Tankless Water Heater Use and Care Guide • 59
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 tempera-
ture.
2. 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.
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 55 to properly drain the water heater.
Remove the bypass valve and inspect for any debris or damage. Replace if need-
ed.
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 dam-
aged 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.
60 • 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 34.
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 damaged 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 • 61
TROUBLESHOOTING
Error
Code
Error Type Procedure
E403 Fan - Low Speed
1.
Check the fan motor wiring. Correct any loose connec ons and replace any dam-
aged 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 con-
nec 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 Ven ng 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 con-
nec 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 con-
nec ons and replace any damaged wire/connector.
2. If the error s ll occurs, contact a qualifi ed service technician.
E416 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.
62 • Residen al Gas Water Heater Use and Care Guide
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 con-
nec ons and replace any damaged wire/connector.
2. Check the inlet & heat exchanger thermistor sensor wires for a short or discon-
nec on. Correct any loose connec ons and replace any damaged wire/connec-
tor.
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 service 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 39. "
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.
Residen al Gas Water Heater Use and Care Guide • 63
COMPONENT LIST
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 temperature when enabled. If it is disabled, press the heater’s ON/OFF
bu on to enable the heater’s opera on.
2. Verify that the heater’s water shutoff valves are open.
3. Check the fl ow sensor wires for a short or disconnec on. Correct any loose con-
nec 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 need-
ed.
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.
64 • Residen al Gas Water Heater Use and Care Guide
COMPONENT LIST
1
18
22
3
20
4
6
21
28
14
25
13
2
7
12
34
Residen al Gas Water Heater Use and Care Guide • 65
COMPONENT LIST
18
22
3
5
6
4
28
20
14
27
12
10
24
26
21
16
8
9
15
19
7
66 • Residen al Gas Tankless Water Heater Use and Care Guide
COMPONENT LIST
18
3
5
6
20
14
7
12
10
23
21
16
22
15
24
Residen al Gas Tankless Water Heater Use and Care Guide • 67
COMPONENT LIST
29
17
32
31
30
33
COMPONENT LIST
68 • Residen al Gas Tankless Water Heater Use and Care Guide
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
COMPONENT LIST
Residen al Gas Tankless Water Heater Use and Care Guide • 69
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)
70 • Residen al Gas Tankless Water Heater Use and Care Guide
NOTES
Residen al Gas Tankless Water Heater Use and Care Guide • 71
Copyright © 2023, A. O. Smith.
All Rights Reserved
