American Water Heater 240HX3 User manual

Gas Tankless Water HeaterTM
Do not install the water heater with a recircula-
tion loop. Suitable for potable water heating only.
On-Demand Water Heater
Installation Manual and Owner’s Guide
If you have any questions, please call
or write to:
In the United States
500 Tennessee Waltz Parkway
Ashland City, TN 37015
Toll Free: 1-877-737-2840
- Do not store or use gasoline or other
flammable vapors and liquids in the vicinity
of this or any other appliance.
- WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electric switch; do not
use any phone in your building.
• Immediately call your gas supplier from
a neighbor's phone. Follow the gas
supplier's instructions.
• If you cannot reach your gas supplier, call
the fire department.
- Installation and service must be performed
by a qualified installer, service agency or the
gas supplier.
WARNING
If the information in these
instructions is not followed
exactly, a fire or explosion may
result causing property damage,
personal injury or death.
Keep this manual near the water heater for future reference whenever maintenance, adjustment, or
service is required.
FEATURING
• ENDLESS HOT WATER
• ON-DEMAND USAGE
• COMPACT, SPACE SAVING
• ENERGY CONSERVATION
• COMPUTERIZED SAFETY
• NO PILOT LIGHT
• X3™ TECHNOLOGY
• Complies with SCAQMD Rule
1146.2 for natural gas Low NOx
Emissions of 14 ng/J or 20 ppm.
ANSI Z21.10.3・CSA 4.3
Models
240HX3
340HX3
540HX3

2Page
Contents
CONTENTS
Installation Manual
SPECIFICATIONS .............................................4
INTRODUCTION..............................................5
SAFETY GUIDELINES.....................................6
SAFETY DEFINITION....................................6
GENERAL......................................................6
INSTALLATION ................................................7
CLEARANCES ...............................................9
INCLUDED ACCESSORIES............................9
OPTIONAL ITEMS........................................9
WARNING FOR INSTALLATIONS...............11
 .............12
VENTING INSTRUCTIONS.........................13
Vent termination clearances ....................14
Clearances for sidewall terminations .......15
Clearances for rooftop terminations ........16
Combustion air supply..............................17
Exhaust vent (ABS, PVC, CPVC, or
polypropylene vent) .................................21
DIP switch settings for vent length (ABS,
PVC, CPVC, or polypropylene vent) ..........22
Exhaust vent (Stainless steel vent) ...........25
DIP switch settings for vent length
(Stainless steel vent).................................25
Common venting system ..........................28
GAS SUPPLY AND GAS PIPE SIZING.........30
General .....................................................30
Gas connections .......................................30
Natural Gas supply piping.........................31
Propane (LP) supply piping.......................31
WATER CONNECTIONS .............................32
Pressure relief valve .................................32
X3™ Scale Prevention Technology ............33
CONDENSATE DRAIN ................................34
ELECTRICAL CONNECTIONS.....................36
TEMPERATURE REMOTE CONTROLLER .....37
Included accessories.................................37
Installation ................................................37
APPLICATIONS..............................................39
INITIAL OPERATION .....................................40
Owner's Guide
OPERATING SAFETY .....................................42
NORMAL OPERATION ..................................44

AND REMOTE CONTROLLER ..................44
GENERAL....................................................44
OUTLET WATER TEMPERATURE
SETTING.....................................................45
TEMPERATURE TABLE OF CONTROLLER.45
ADDITIONAL FEATURES............................46
Information mode ....................................46
Unit conversion mode ..............................46
TEMPERATURE SETTINGS ON THE PCB ........47
FLOW .......................................................... 47
FREEZE PROTECTION SYSTEM ................. 48
MAINTENANCE AND SERVICE .................. 49
INLET WATER FILTER CLEANING ................... 49
UNIT DRAINING & POWER OUTAGE
 ................................. 50
MEASURING INLET GAS PRESSURE.................. 51
TROUBLESHOOTING.....................................52
ERROR CODES ...........................................53
Fault analysis error code ..........................54
COMPONENTS DIAGRAM ............................56
PARTS LIST....................................................60
OUTPUT TEMPERATURE CHART ..................63

3Page
Installaon Manual
Installation ManualInstallation Manual
CONGRATULATIONS
Congratulations and thank you for choosing our tankless water
heater. Before use, we recommend that you read through this
installation manual carefully. Keep this manual for future reference.
If you need an additional manual, contact the manufacturer or your
local distributor. You may also download a manual from our website.
When you call, please tell us the product name and the serial number
of your unit written on the rating plate of the water heater.

4Page
Specicaons
Installaon Manual
SPECIFICATIONS
*40 psi or above is recommended for maximum flow.
**Water heater Category — water heaters of other than direct vent type, for outdoor installation, are divided into four categories
based on static pressure produced in the vent and flue loss.
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 with-
out notice and without incurring obligation.
Model
240HX3
Indoor
(AT-H3J-DV-
SCM)
240HX3
Outdoor
(AT-H3J-OS-
SCM)
340HX3
Indoor
(AT-H3S-DV-
SCM)
340HX3
Outdoor
(AT-H3S-OS-
SCM)
540HX3
Indoor
(AT-H3-DV-
SCM)
540HX3
Outdoor
(AT-H3-OS-
SCM)
Natural Gas Input
(Operating Range) BTU/h Min.: 15,000 Max.: 160,000
Min.: 15,000
Max.: 180,000
Min.: 15,000
Max.: 199,000
Propane Input
(Operating Range) BTU/h Min.: 13,000 Max.: 160,000
Min.: 13,000
Max.: 180,000
Min.: 13,000
Max.: 199,000
Gas Connection 3/4" NPT
Water Connections 3/4" NPT
Water Pressure* psi
(MPa)
15 - 150
(0.1 - 1)
Natural gas
Inlet Pressure
" W.C.
(kPa)
Min. 4.0 (1.00)
Max. 10.5 (2.61)
Propane
Inlet Pressure
" W.C.
(kPa)
Min. 8.0 (1.99)
Max. 14.0 (3.48)
Weight lbs.
(kg)
60
(27.4)
60
(27.1)
60
(27.4)
60
(27.1)
62
(27.9)
61
(27.6)
Dimensions
(HxWxD)
inch 22.4 x 17.7 x 10.7
mm 570 x 450 x 272
Ignition Electric Ignition
Electric
Supply VAC/Hz 120/60
Consumption
Operation W/A 72.7 / 0.61 78.2 / 0.65 89.0 / 0.74
Standby W/A 3.1 / 0.03 3.1 / 0.03 4.2 / 0.04
Freeze-
Protection W/A 197/1.7
Water heater category** IV N/A IV N/A IV N/A
The 240HX3/340HX3/540HX3 models do not have Easy-Link or Multi-Unit capability.
NOTICE

5Page
INTRODUCTION
• This manual provides information necessary for the installation, operation, and maintenance of the
water heater.
• The model description is listed on the rating plate attached to the side panel of the water heater.
• Please read all installation instructions completely before installing this product.
• If you have any problems or questions regarding this equipment, consult the manufacturer or its
local representative.
• This equipment is an on-demand, tankless water heater designed to efficiently supply endless hot
water for your needs when properly sized and installed.
• These high efficiency models have a built-in secondary heat exchanger that absorbs latent heat
from the exhaust gas.
• The Indoor models are only to be installed indoors. The Outdoor models are only to be installed
outdoors.
• The principle behind tankless water heaters is simple:
Exhaust
Drain plug
detector
Secondary
heat exchanger
Intake port
(Indoor only)
Cold
water
inlet
Gas
Hot water
outlet
Flow sensor/
Water control
valve
X3™ Cartridge
Gas valves
Igniter
Burner
Inlet thermistor
Outlet
thermistor
Bypass valve
(540HX3 only)
Primary
heat exchanger
Exhaust HL
(Indoor only)
Exhaust thermistor
(Indoor only)
HX thermistor
(540HX3 only)
Computer board
Fan motor
Condensate
drain port
Hi limit switch
*This diagram illustrates tankless water heater design concepts only and does not accurately represent the
water heater’s physical description.
1. A hot water tap is turned on.
2. Water flows through the flow sensor, then through the X3™ Scale Prevention Technology cartridge.
3. The computer initiates the fan motor and gas valve to let gas flow through the heater and sends a signal to
the igniter to create an ignition spark.
4. The gas ignites and flames appear within the burner chamber.
5. Water is heated as it flows through the heat exchanger.
6. Using thermistors to measure temperatures throughout the water heater, the computer modulates the gas
and water valves to ensure proper output water temperature and hot water outflows.
7. When the tap is turned off, the unit shuts down.
Introducon
Installaon Manual

6Page
GENERAL
1. Follow all local codes, or in the absence of local codes, follow the current edition of the National Fuel Gas
Code: ANSI Z223.1/NFPA 54 in the USA.
2. Properly ground the unit in accordance with all local codes or in the absence of local codes, with the
National Electrical Codes: ANSI/NFPA 70.
3. Carefully plan where you intend to install the water heater. Please ensure:
• Your water heater will have enough combustion air and proper ventilation.
• Locate your heater where water leakage will not damage surrounding areas. (Please refer to page 8.)
4. Check the rating plate for the correct GAS TYPE, GAS PRESSURE, WATER PRESSURE and ELECTRIC RATING.
• If this unit does not match your requirements, do not install and consult with the manufacturer.
5. If any problem should occur, turn off all hot water taps and turn off the gas. Then call a trained
technician, the gas company, or the manufacturer.
Safety Guidelines
Installaon Manual
SAFETY GUIDELINES
SAFETY DEFINITION
WARNING
Indicates an imminently hazardous situation which, if not avoided, could result in
death or serious injury.
CAUTION
Indicates an imminently hazardous situation which, if not avoided, could result in
minor or moderate injury.
Indicates an imminently hazardous situation which, if not avoided, will result in
death or serious injury.
DANGER
Indicates information considered important but not hazard related.
NOTICE
WARNING
• Water temperatures over 125 °F (52 °C) can cause severe burns instantly or death from
scalding. The water temperature is set at 120 °F (50 °C) from the factory to minimize any
scalding risk. Before bathing or showering always check the water temperature.
• To reduce the risk of scalding, install Thermostatic Mixing Valves (temperature limiting valves)
at each point of use.
• Do not store or use gasoline or other flammables, vapors, or liquids in the vicinity of this
appliance.
• Do not reverse the water and/or gas connections as this will damage the gas valves and can
cause severe injury or death. Follow the diagram on page 32 when installing your water
heater.
• Should overheating occur or the gas supply fails to shut off, turn off the manual gas control
valve to the appliance.
• Do not use this appliance if any part has been in contact with or been immersed in water.
Immediately call a qualified installer or service agency to replace a flooded water heater. Do
not attempt to repair the unit. It must be replaced.
• Do not disconnect the electrical supply if the ambient temperature will drop below freezing.
The Freeze Protection System only works if the unit has electrical power. The warranty will
not be covered if the heat exchanger is damaged due to freezing. Refer to the sections on
the Freeze Protection System on page 48 and on Unit Draining & Power Outage (Freeze
protection) on page 50 for more information.
• Failure to observe these warnings could result in severe personal injury or death.

7Page
INSTALLATION
GENERAL
1. Follow all local codes, or in the absence of local codes, follow the current edition of the National Fuel Gas
Code: ANSI Z223.1/NFPA 54.
2. All gas water heaters require careful and correct installation to ensure safe and efficient operation. This
manual must be followed exactly. Read the "Safety Guidelines" Section.
3. The manifold gas pressure is preset at the factory. It is computer controlled and should not need
adjustment.
4. Maintain proper space for servicing. Install the unit so that it can be connected or removed easily. Refer
to the "Clearances" Section on page 9 for proper clearances.
5. The water heater must be installed in a location where the proper amount of combustion air will be
available to it at all times without obstructions, or the indoor heater must be direct vented. See pages 13
to 29.
6. Install the water heater so it is level (left-to-right & front-to-back) and plumb (vertically).
7. Electrical service to the water heater requires a means of disconnection. This will allow power to the
water heater to be shut off for servicing and safety purposes.
8. Do not install the unit where the exhaust vent is pointing into any opening in a building or where the
noise may disturb your neighbors. Make sure the vent termination meets the required clearance from
any doorway or opening to prevent exhaust from entering a building. (Refer to pages 8, 11, 14 and 15.)
Check local code requirements prior to installation.
9. Carefully plan the installation location of the heater and vent terminations. Contaminants such as
aerosols, lint, and fine powders (including flour) can clog the air intake and reduce the operation of the
fan. This, in turn, can cause improper combustion and reduce the life of the water heater. Regularly
ensure that the area around the water heater, vent termination, and air intake are free of dust, debris,
and other contaminants. In environments with a high level of contaminants (laundry facilities, hair salons,
pet salons, chemical plants, commercial kitchens, etc.), direct venting is required.
10. The Indoor models are to be installed indoors only. These units are equipped with a thermistor and
hi-limit switch for the exhaust gas, detecting excess temperatures within the flue and enabling the unit
to safely stop operations if needed. These components are always monitoring exhaust gas conditions in
order to prevent heat damage to ABS, PVC, CPVC, or polypropylene (Plastic) venting if ABS, PVC, CPVC,
or polypropylene is used. If the exhaust gas temperature exceeds 140 °F (60 °C), these components will
enable the unit to safely stop operations. These components are not installed on the outdoor models
since the exhaust vent is built-in.
• 
supply pipe. The intake pipe must be sealed airtight. Refer to pages 13 to 29 for more detail.
• Terminating the venting through a sidewall is recommended for the direct-vent system.
• Running the exhaust vent and the intake pipe parallel is recommended.
• Terminating the exhaust and intake on the same wall/surface is recommended. Terminating in the
same pressure zone allows for pressure balancing, which prevents nuisance shutdowns.
• Only install the water heater in a heated area where below freezing temperatures cannot occur.
The warranty does not cover damage caused by freezing.
• The water heater must be securely mounted to a wall or other suitable structure.
• The venting system shall be installed in accordance with the water heater manufacturer's and
venting system manufacturer's instructions.
11. The Outdoor models must only be installed outdoors and only in an area with mild, temperate climates.
The Outdoor model shall be wall-mounted or mounted on a stand. Locate the Outdoor model in an open,
unroofed area and maintain the following minimum clearances: There is a 3 in (76 mm) clearance from
the left and right sides of the unit to combustible and non-combustible surfaces.
Installaon
Installaon Manual

8Page
Installaon
Installaon Manual
WARNING
• Installation and service must be performed by a qualified installer (for example, a licensed
plumber or gas fitter). Otherwise, the warranty will be void.
• The installer (licensed professional) is responsible for the correct installation of the water
heater and for compliance with all national, state/provincial, and local codes.
• The manufacturer does not recommend installing the water heater in a pit or location where
gas and water can accumulate.
• Do not attach the gas line to the water heater until after the gas line system pressure test for
leaks has been completed. See page 30 for additional information.
• Do not install or locate the vent terminal pointing toward any operating window, door, opening
into a building or other area where people gather, where combustion gases could create a
nuisance or hazard or cause property damage.
• Do not install the air intake next to any source of airborne debris, such as a clothes dryer, that
can cause debris to be trapped inside the combustion chamber, unless the system is direct-
vented.
• Do not install the unit where water, debris, or flammable vapors may get into the flue terminal
or the air intake line.
• The manufacturer does not recommend installing the water heater in an attic due to safety
issues. If you install the water heater in an attic:
- Make sure the unit will have enough combustion air and proper ventilation. Failure to do
so could lead to carbon monoxide poisoning or death.
- Keep the area around the water heater clean. When dust collects on the flame sensor, the
water heater will shut down on an error code.
- Place the unit where it will allow easy access for service and maintenance.
- A drain pan, or other means of protection against water damage, is recommended to be
installed under the water heater in case of leaks. See the NOTICE below.
• The water heater must be securely mounted to a wall or other suitable structure so that it is
level (left-to-right & front-to-back) and plumb (vertically).
• Failure to observe these warnings could result in severe personal injury, death, and/or
property damage.
NOTICE
• The warranty will not cover damage caused by water quality.
- Only potable water can be used with this water heater. Do not introduce pool or spa
water, or any chemically treated water into the water heater.
- Introduction of water with iron greater than 0.3 mg/L.
- Water pH levels must be between 6.5 and 8.5.
- Well water must be treated.
• The manufacturer recommends direct venting when the water heater is installed in beauty
salons, dry cleaners or any other locations in which such chemicals are present in the air.
Some chemicals used in beauty salons or dry cleaners may affect the flame sensor. In such
cases, the water heater may not work properly.
• Although the water heater is designed to operate with minimal sound, the manufacturer
does not recommend installing the unit on a wall adjacent to a bedroom, or a room that is
intended for quiet study or meditation, etc.
• Locate your water heater close to a drain where water leakage will not do damage to
surrounding areas. As with any water heating appliance, the potential for leakage at some
time in the life of the product does exist. A drain pan, or other means of protection against
water damage, is recommended to be installed under the water heater in case of leaks. In
addition, you may install an active 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
combustion air flow.
• This water heater is not suitable for combination water (potable) heating, space heating, and/
or recirculation

9Page
CLEARANCES
Installaon
Installaon Manual
Model Top Bottom Front Back Sides
Indoor 12 in
(305 mm)
18 in
(458 mm)
4 in*
(102 mm)
0.5 in
(13 mm)
3 in
(76 mm)
Outdoor 36 in
(914 mm)
18 in
(458 mm)
24 in
(610 mm)
0.5 in
(13 mm)
3 in
(76 mm)
*24 inches (610 mm) recommended for maintenance.
OPTIONAL ITEMS
#Model 240HX3
Indoor
240HX3
Outdoor
340HX3
Indoor
340HX3
Outdoor
540HX3
Indoor
540HX3
Outdoor
1. Temperature remote
controller ✓ ✓ ✓
2. Pipe cover ✓ ✓ ✓ ✓ ✓ ✓
3. Neutralizer kit ✓ ✓ ✓ ✓ ✓ ✓
4. 3" PVC concentric
termination ✓ ✓ ✓
5. Recess box ✓ ✓ ✓
6. Non-return valve ✓ ✓ ✓
7. 4" PVC Adapter
(for Non-return valve) ✓ ✓ ✓
INCLUDED ACCESSORIES
Check that these items below are included with the water heater.
Installation manual
and owner’s guide
Temperature remote controller kit
Outdoor models only
(Refer to pp. 10 and 35.)
Bird screen
Indoor models only X3™ cartridge
Qty: 2
Maintain all clearances around the water heater. Failure to do so could create a fire hazard,
potentially leading to death, serious injury, and/or property damage.
WARNING
Back
Side
Front
Side
Top

100209924 (TM-RE42) 100282480 100314491

10 Page
Installaon
Installaon Manual
3. Neutralizer kit: 100112159
The 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. (Refer to pages 34 and 35.)
1. Temperature remote controller:
100209924 (TM-RE42)
The temperature remote controllers have
three functions. It allows the output
temperature from the water heater
to be adjusted and it also works as a
diagnostic tool and it provides a concise
error code whenever there is a problem with the unit.
See the Troubleshooting Section (pages 53 to 55) for
information on possible error codes.
4. 3" PVC concentric termination: 100112163


through a sidewall instead of two separate penetrations for the intake
and exhaust piping. The termination includes a bird screen, restricting
small animals, pests, and foreign objects from entering into the vent
system.
2. Pipe cover:
100112718 (TH-PC03) for 240HX3/340HX3/540HX3
The pipe cover protects the plumbing
pipes to the water heater from
unexpected adjustments. This pipe
cover is fixed to the bottom of the
water heater, which hides the plumbing
and improves the visual aspects of the
whole installation for the water heater.
7. 4" PVC Adapter: 100113129
6. Non-return valve: 100113130
It is a must-have item for common
venting system. It prevents the
escape of combustion gas through
non-operating appliances. (Refer to
pages 28 and 29.)
This adapter transitions from the
Non-return valve outlet to 4"
schedule 40 PVC pipe.
5. Recess box:
It allows for “clean” installations. The water heater fits inside the recess box, which hides and protects the
whole water heater and plumbing.
For new construction application s -with flange
100306285
For retrofit applications - no flange
100298009

11 Page
Installaon
Installaon Manual
WARNING FOR INSTALLATIONS
FOR YOUR SAFETY, READ BEFORE INSTALLATION:
Do not install the heater where water, debris or
flammable vapors may get into the flue terminal.
This may cause damage to the heater and void
the warranty.
Do not have the vent terminal pointing toward
any opening into a building. Do not locate your
heater vent terminal, and air intake in a pit or
location where gas and water can accumulate.
Do not install next to a dryer or any source
of airborne debris that can be trapped inside
the combustion chamber, unless the system
is direct-vented.
Prohibited Prohibited






Ensure that you meet the minimum clearances
shown below for a direct vent termination:
Locate the outdoor water heater so it's vent terminal
meets the following clearances. Locate the vent terminal
of an indoor heater to meet the following clearances:



Outside
corner Inside
corner



4 � min.
4 � min.
4 � min.
Ensure that you meet the minimum clearances
shown below for outdoor vent termination:

12 Page
HIGH-ALTITUDE INSTALLATIONS
WARNING
• Adjust the appropriate DIP switches according to model and elevation as shown
below. DO NOT adjust the other DIP switches.
• Turn off the power supply to the water heater before changing the DIP switch
settings.
• Failure to observe these warnings could lead to carbon monoxide poisoning or
death.
Installaon
Installaon Manual
NOTE: The dark squares indicate the correct DIP switch positions.
540HX3
Lower bank of DIP switches
Bank of DIP switches
240HX3/340HX3
Indoor models
0 to 2,000 ft
(0 to 610 m)
(DEFAULT)
2,001 to
3,000 ft
(611 to 914 m)
3,001 to
5,000 ft
(915 to 1,524 m)
5,001 to
7,500 ft
(1,525 to 2,286 m
7,501 to
10,100 ft
(2,287 to 3,078 m)
240HX3/340HX3
OFF
ON
1 2 3 4 5 6 7 8 9 10
No. 3 : OFF
No. 4 : OFF
No. 5 : OFF
OFF
ON
1 2 3 4 5 6 7 8 9 10
No. 3 : OFF
No. 4 : O N
No. 5 : OFF
OFF
ON
12345678910
No. 3 : OFF
No. 4 : OFF
No. 5 : ON
OFF
ON
12345678910
No. 3 : OFF
No. 4 : O N
No. 5 : O N
OFF
ON
12345678910
No. 3 : O N
No. 4 : O N
No. 5 : O N
540HX3
(Lower bank of
DIP switches)
OFF
ON
1 2 3 4 5 6
No. 2 : OFF
No. 3 : OFF
No. 4 : OFF
OFF
ON
1 2 3 4 5 6
No. 2 : OFF
No. 3 : O N
No. 4 : OFF
OFF
ON
1 2 3 4 5 6
No. 2 : OFF
No. 3 : OFF
No. 4 : O N
OFF
ON
1 2 3 4 5 6
No. 2 : OFF
No. 3 : O N
No. 4 : O N
OFF
ON
1 2 3 4 5 6
No. 2 : O N
No. 3 : O N
No. 4 : O N
Altitude
DIP switches
Installation altitude
The maximum certified
or allowable installed
altitude is 10,100 ft
(3,078 m) for indoor
models and 6,000 ft
(1,829 m) for outdoor
models.
Outdoor models
0 to 2,000 ft
(0 to 610 m)
(DEFAULT)
2,001 to
4,000 ft
(611 to 1,219 m)
4,001 to
6,000 ft
(1,220 to 1,829 m)
240HX3/340HX3
OFF
ON
1 2 3 4 5 6 7 8 9 10
No. 3 : OFF
No. 4 : OFF
No. 5 : OFF
OFF
ON
12345678910
No. 3 : OFF
No. 4 : OFF
No. 5 : O N
OFF
ON
1 2 3 4 5 6 7 8 9 10
No. 3 : O N
No. 4 : OFF
No. 5 : O N
540HX3
(Lower bank of
DIP switches)
OFF
ON
1 2 3 4 5 6
No. 2 : OFF
No. 3 : OFF
No. 4 : OFF
OFF
ON
1 2 3 4 5 6
No. 2 : OFF
No. 3 : OFF
No. 4 : O N
OFF
ON
1 2 3 4 5 6
No. 2 : O N
No. 3 : OFF
No. 4 : O N
Altitude
DIP switches

13 Page
Installaon
Installaon Manual
VENTING INSTRUCTIONS
• Improper venting of this appliance can result in excessive levels of carbon monoxide which
can result in severe personal injury or death.
• Improper installation can cause nausea or asphyxiation, severe injury or death from carbon
monoxide and flue gases poisoning. Improper installation will void product warranty.
• When installing the vent system, all applicable national and local codes must be followed.
If you install thimbles, fire stops or other protective devices and they penetrate any
combustible or noncombustible construction, be sure to follow all applicable national and
local codes.
WARNING
The Indoor model must be vented in accordance with "Venting of Equipment" in the current edition of the
National Fuel Gas Code: ANSI Z223.1/NFPA 54 as well as applicable local building codes.
The use of venting materials approved for Category III/IV appliances is required. In addition, PVC (solid core),
CPVC, ABS, and polypropylene are approved for use with the indoor models. For details, please refer to the
Exhaust Vent (ABS, PVC, CPVC, or Polypropylene Vent) Section on pages 21 to 24.
General rules for venting water heaters:
• Place the water heater as close as possible to the vent termination.
• The vent collar of the water heater must be fastened directly to an unobstructed vent pipe.
• Do not weld the vent pipe to the water heater’s vent collar.
• Do not cut or alter the vent collar of the unit.
• The vent must be easily removable from the top of the water heater for normal service and inspection of
the unit.
• The water heater vent must not be connected to any other gas appliance or vent stack except an approved
common-venting system. Refer to pages 28 and 29.
• Avoid using an oversized vent pipe or using extremely long runs of the pipe unless it is part of an approved
common vent system.
• Air supply pipe can be made of ABS, PVC (solid core), CPVC (solid core), polypropylene, corrugated stainless
steel, or Category lll/IV stainless steel. Regarding exhaust pipe, refer to pages 21 to 27.
• Use of cellular core PVC (ASTM F891), cellular core CPVC, or Radel® (polyphenylsulfone) in nonmetallic
venting systems is prohibited. Covering non-metallic vent pipe and fittings with thermal insulation is
prohibited.
• Sidewall venting is recommended for the Indoor model. Vertical venting (roof termination) is acceptable.
• Slope horizontal venting sections 1/4" upwards for every 12" (300 mm) toward the termination or
according to local and state codes, or in the absence of local or state codes, the current edition of the
National Fuel Gas Code, ANSI Z223.1 (NFPA 54)
• The manufacturer recommends running the exhaust vent and the intake pipe as parallel as possible.
• For rooftop venting, a rain cap or other form of termination that prevents rain water from entering into the
water heater must be installed.
• Do not terminate vent into a chimney. If the vent must go through the chimney, the vent must run all the
way through the chimney with approved vent pipe.
• The water heater shall not be connected to a chimney flue serving a separate appliance, designed to burn
solid fuel.
• When an existing Category I appliance is removed or replaced, the original venting system may no longer
be sized to properly vent the attached water heater. An improperly sized venting system may cause
formation of condensate, leakage, and spillage and so on. Follow all instructions in this manual.
General rules for vent terminations:
• Avoid locating the water heater vent termination near any air intake devices. These fans can pick up the
exhaust flue products from the water heater and return them to the building. This can create a health
hazard.
• Locate the vent termination so that it cannot be blocked by any debris, at any time. Most codes require
that the termination be at least 12 in (305 mm) above grade and anticipated snow level, but the installer
may determine if it should be higher depending on the job site condition and applicable codes.
• A proper sidewall termination is recommended when the water heater is vented through a sidewall.
• Regarding the clearances from the exhaust termination to the air inlet or opening, refer to pages 14 to 16.

14 Page
Installaon
Installaon Manual
D
L
B
V
V
V
V
V
V
FJ
BB
C
B
B
B
B
A
K
MX
X
B
15 �
I
E
H
Inside
corner detail
V
G
A
Fixed
closed
Fixed
closed
Operable
Operable
Regulator vent outlet
In the event no regulator is present,
H and I can be disregarded
Legend:
V
X
= Vent terminal
= Air supply inlet
= Area where terminal is not permi�ed
US Installations1
Direct vent Other than direct vent
AClearance 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 1 ft
(30 cm)
4 ft (1.2 m) below or to side of
opening;
1 ft (30 cm) above opening
CClearance to permanently closed window 0 0
D
Vertical clearance to ventilated soffit located above
the terminal within a horizontal distance of 2 ft (61
cm) from the center line of the terminal
3 ft (91 cm) 3 ft (91 cm)
EClearance to unventilated soffit 3 ft (91 cm) 3 ft (91 cm)
FClearance to outside corner 2 ft (61 cm) 2 ft (61 cm)
GClearance to inside corner 2 ft (61 cm) 2 ft (61 cm)
HClearance to each side of center line extended above
meter/regulator assembly * *
IClearance to service regulator vent outlet * *
J
Clearance to non-mechanical air supply inlet to
a building or the combustion air inlet to any other
appliance.
1 ft
(30 cm)
4 ft (1.2 m) below or to side of
opening;
1 ft (30 cm) above opening
KClearance to mechanical air supply inlet 3 ft (91 cm) above if within
10 ft (3 m) horizontally. 3 ft (91 cm) above if within 10 ft (3 m) horizontally.
LClearance above paved sidewalk or paved driveway
located on public property 7 ft (213 cm) 7 ft (213 cm)
MClearance under veranda, porch deck, or balcony 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 soffit vents or crawl space vents or other areas where condensate or vapor could create a nuisance or hazard or cause property damage; or
• where condensate vapor could cause damage or could be detrimental to the operation of regulators, relief valves, or other
equipment.
Notes:
1) In accordance with the current ANSI Z223.1/NFPA 54, National Fuel Gas Code
2) If locally adopted installation codes specify clearances different than those illustrated, then the most stringent clearance shall prevail.
3) Blocking air supply and exhaust vent by snow may cause incomplete combustion and an appliance failure. Install the termination by
providing sufficient clearance from anticipated snow line in accordance with local code or manufacture's instructions and make sure
there in no blockage.
4) Provide an appropriate clearance between a vent termination and a building to prevent degradation to building materials caused by
flue gases.
5) Water heaters installed outdoors follow the Other Than Direct Vent clearances.
-Vent terminaon clearances-

15 Page
Installaon
Installaon Manual
-Clearances for sidewall terminaons-
Multiple Sidewall Terminations
An exhaust termination must be at least
1 ft (305 mm) away from another exhaust
termination. An exhaust termination must
also be at least 2 ft (610 mm) away from an
inside corner. (If the adjacent wall is less than
2 ft (610 mm) of length, the minimum required
distance away from the inside corner will be
equal to the length of that adjacent wall.)
Multiple DV Sidewall Terminations
A direct vent (DV) termination must be at least
1 ft (305 mm) away from other direct vent
terminations.
A direct vent termination must also be at least
2 ft (610 mm) away from an inside corner. (If
the adjacent wall is less than 2 ft (610 mm) of
length, the minimum required distance away
from the inside corner will be equal to the
length of that adjacent wall.)
Ancipated Snow level
Exhaust
Terminaon
2 
(610 mm)
min.
1 
(305 mm)
min.
1 
(305 mm)
min.
Inside
corner
Inside
corner
Ancipated Snow level
2 
(610mm)
min.
1 
(305 mm)
min.
1 
(305 mm)
min.
Combined
intake and
exhaust
terminaon
For direct vent sidewall
terminations that use two
separate penetrations for the
intake and exhaust, keep the
termination clearances shown in
the diagrams on the right.
X3™ CARTRIDGE is not shown.
Improper installation can result in carbon monoxide poisoning or death. Follow all local and
national codes in regards to proper termination clearances. In the absence of such codes, the
clearances below can be used as guidelines. Local codes supersede these guidelines.
WARNING
1 ft (305 mm) min.
0.5 ft
(159 mm) min.
Exhaust
Intake
Exhaust
Intake
<Case 2>
1 ft (305 mm)
min.
0.5 ft
(159 mm) min.
Exhaust
Intake
Exhaust
Intake
<Case 1>
Exhaust
termination
2 ft (610 mm)
min.
Exhaust and/or direct
vent sidewall terminations
should be at least 2 ft
(610 mm) away from an
opposite surface/wall. Do
not place the termination
directly in front of an
opening into a building.

16 Page
Installaon Manual
Installaon
-Clearances for rooop terminaons-
Follow all local and national codes in regards to proper termination 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.
WARNING
• Exhaust terminations must be at least 1 ft (305 mm) away from any obstructions.
• Minimum spacing between multiple terminals:
• intake terminals: 1 ft (305 mm) spacing between each
• exhaust terminals: 1 ft (305 mm) spacing between each
• The exhaust termination must be a horizontal distance of at least 2 ft (610 mm) from a
wall or surface unless specified differently by local code.
• Failure to observe this warning may result in severe personal injury or death.
WARNING
Angled roof termination
Ancipated snow level
2  (610 mm) min.
1 
(305 mm)
min.
1 
(305 mm)
min.
1 
(305 mm)
min.
Exhaust
Intake
Multiple flat roof terminations













Exhaust Exhaust
Intake
Intake
Flat roof termination
Ancipated snow level
3  (914 mm) min.
1 
(305 mm)
min.
1 
(305 mm)
min.
Exhaust
Intake
Multiple angled roof terminations
1 
(305 mm)
min.
1 
(305 mm)
min.
3 
(914 mm)
min.
1 
(305 mm)
min.
1 
(305 mm)
min.
Ancipated snow level
2 
(610 mm)
min.
1 
(305 mm)
min.
Exhaust Exhaust
Intake
Intake

17 Page
-Combuson air supply-
This gas water heater requires an adequate source of clean air for combustion and
ventilation. Without sufficient air, your water heater may not operate properly and
may emit excessive and abnormal amounts of carbon monoxide which may result in
carbon monoxide poisoning or death.
WARNING
The guidelines in this section apply to installations within the United States. All U.S.
installations must conform to the National Fuel Gas Code, ANSI Z223.1/NFPA 54 (cur-
rent edition) and local codes.
NOTICE
Before installing the water heater, you must determine the amount of air needed to supply this water heater and


Check for Chemicals:


chemicals is not covered by the warranty.
WARNING!
In all cases, ensure that corrosive chemicals are not present at the air intake. Presence of such chemicals at the
air intake could result in death, personal injury, or property damage.
due to chemicals include:
• Beauty salons
• Photo processing labs
• Indoor pools
• 
• Chemical storage areas
• Restaurants
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.
Does your installation space have sufficient combustion air?





the water heater



-
ances (e.g., water heaters, furnaces, clothes dryers) in the same area. Do not include appliances that are direct
vented. Refer to the following example.
Installaon
Installaon Manual

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Your water heater’s BTU/h rating is on the rating plate. The BTU/h ratings should be on the other appliances’
rating plates. If you have trouble determining the BTU/h ratings, contact the manufacturer or have a qualified
person determine the ventilation requirements.
NOTICE:

Gas Burning Appliance 
Gas Water Heater 199,000
Furnace 75,000
Dryer 20,000
Total 294,000
Example: Gas Burning Appliance 
Gas Water Heater
Total
Your
appliances:
Calculate the air volume of the room
Air requirements depend on the size of the room.
32
If there are large objects in the room (e.g., refrigerator, furnace, car), subtract their volume from the volume of the

Air Volume = Room Volume - Object Volume
NOTE:
Calculate required air volume
3(1.42
m3) per 1,000 BTU/h of the total input for all gas burning appliances in the same area.
33/ 1000 (btu/h)
Example:
3
If the air volume of the room is less than the required air volume, you must direct vent the water heater or


If the air volume of the room is greater than the required air volume, it may be possible to install the water heat-

-
es, whole house fans, and clothes dryers draw air out of your home. If they draw air out faster than it can be

-
vent the water heater or install an adequate


Install with outside ventilation


Supplying outside air to the water heater typically requires two openings. One opening must be within 12 in (305 mm)

not preferred, you may use a single opening to outside air if the minimum free area is sized according to Table 1. Two



Installaon
Installaon Manual

19 Page
Determine type of ventilation
-

1. Direct to outdoors
2. 
3. Horizontal ducts-Single opening (not recommended; must be at least 100 in2(645 cm2) . Not appropriate for con-
3(1.42 m3)
4. From a larger room inside the house (not recommended – refer to "Calculate the air volume of the room" above to
determine if the combined volume of the rooms may be adequate).
Determine minimum free area required for each vent opening
-
fore beginning”) and the type of vent used. Table 1 provides the minimum free area for each vent opening depending on the

Calculate minimum size of vent openings and ducts

louvers or grilles to protect the opening. The louver or grill itself blocks some of the free area, so the opening may need to be
larger to meet the minimum free area requirements.


2(645 cm2) of free area would need 134 in2
(865 cm222).
If you do not know the % free area for your louver or grill, use the following values:
• 
• 

• Each vent opening must be no smaller than 100 in2(645 cm2).
• 
• Rectangular ducts must have a minimum dimension of no less than 3 in (76 mm).
• All screens must have mesh ¼” or larger.
• 

• 
Check that air source is clean and free of chemicals

-
rine, and chlorine. Be sure that air at the vent inlets is free of such chemicals.
See graphics on next page.
Table 1

indoor spaces.

Opening Source Minimum Free Area
Direct to outdoors* 1 in2(6.5 cm2) per 4,000 BTU/hr (see Figure 1, 2)
 1 in2(6.5 cm2) per 4,000 BTU/hr (see Figure 3)
Horizontal ducts 1 in2(6.5 cm2) per 2,000 BTU/hr (see Figure 4)
Single Opening 1 in2(6.5 cm2) per 3,000 BTU/hr (see Figure 5)
Two permanent openings
to another room**
1 in2(6.5 cm2) per 1,000 Btu/hr (see Figure 6)
Opening: 100 in2 (645 cm2)MIn
Minimum dimension of air openings:
no less than 3 in (76 mm)

an outside wall.
-

Installaon
Installaon Manual

20 Page

X3™ CARTRIDGE NOT SHOWN FOR CLARITY.
Gable vent
to outdoors
Install above
insulaon
Outlet air to
ac 1 in2 (6.5 cm2)
per 4,000 btu/h
Inlet air from
the crawl space
Open foundaon vent
Confined
Space
Alternate
Air Inlet
1 in2 (6.5 cm2)
per 4,000 btu/h
Figure 1 - Direct to outdoors openings
 duct openings
Outlet air to
ac 1 in2(6.5 cm2)
per 4,000 btu/h
Inlet air duct
1 in2 (6.5 cm2)
per 4,000 btu/h
Confined
Space
12” (305 mm)
maximum
Gable vent
to outdoors
Install above
insulaon
Figure 5 - Single opening
Confined
Space 1 in2 (6.5 cm2)
per 3,000 btu/h
Alternave
Opening
Locaon
Figure 6 - Two permanent openings
Two permanent
Openings
1 in2 (6.5 cm2)per
1,000 btu/h
12” (305 mm)
maximum
12” (305 mm)
maximum
Confined
Space
Figure 4 - Horizontal duct openings
1 in2 (6.5 cm2)
per 2,000 btu/h
Confined
Space
Outlet
Inlet
Outdoor
Air Ducts
1 in2 (6.5 cm2)
per 2,000 btu/h
Figure 2 - Direct to outdoors openings
Two permanent openings
Two permanent
Openings
1 in
2 (6.5 cm2)
per 4,000 btu/h
12” (305 mm)
maximum
12” (305 mm)
maximum
Confined
Space
Installaon
Installaon Manual