Takagi 160X3P User manual

Gas Tankless Water Heater™
Suitable for water (potable) heating only.
If you have any questions,
please call or write to
USA: 500 Tennessee Waltz Parkway
Ashland City, TN 37015
1-877-737-2840
CANADA: 599 Hill Street West
Fergus, ON N1M 2X1
1-888-479-8324
On-Demand Water Heater
Installation Manual and Owner’s Guide
ANSI Z21.10.3 • CSA 4.3
FEATURING
• INTEGRATED RECIRCULATION PUMP
• ENDLESS HOT WATER
• ON-DEMAND USAGE
• COMPACT, SPACE SAVING
• ENERGY CONSERVATION
• COMPUTERIZED SAFETY
• NO PILOT LIGHT
• Complies with SCAQMD Rule 1146.2 for natural gas
NOx emissions of 14 ng/J or 20 ppm.
• EASY-LINK SYSTEM
• X3™ TECHNOLOGY
Keep this manual near the water heater for future reference whenever maintenance, adjustment or service is required.
– 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.
160X3P
180X3P
199X3P
Model
R
DR

CONTENTS
On-Demand Water Heater
Installation Manual and Owner's Guide
SPECIFICATIONS .............................................4
DIMENSIONS...............................................5
SAFETY GUIDELINES.....................................6
SAFETY DEFINITION....................................6
INTRODUCTION............................................7
INSTALLATION ................................................8
1 Read this section before you start ............8
2 Familiarize yourself with the components......11
Included items/Optional items .......................11
3 Installation environment and unit
clearances. ...............................................12
4 Mounting the water heater.....................13
5 General instructions of venting. ...............14
How to install venting into the water heater ......15
DIP switch settings for the vent style................16
6 Combustion air supply .............................17
Combustion air supply options .......................20
Direct vent air intake moisture protection .........21
7 Exhaust vent for Indoor installation .........22
ABS,PVC,CPVC, or polypropylene vent ........22
-1 Direct Vent installation examples ............23
-2 Power Vent installation examples ............23
-3 Vent terminations...............................24
8 Clearance .................................................26
Vent termination clearances ....................26
Clearances for sidewall terminations .......27
Clearances for rooftop terminations ........28
9 Outdoor installation .................................29
10 Gas supply and gas pipe sizing................31
Gas connections .......................................31
Natural Gas supply piping.........................32
Propane (LP) supply piping.......................32
11 LP gas conversion ....................................33
Gas conversion procedure........................33
Check combustion status..........................35
..................................................35
12 Water connections ..................................36
Recirculation pump modes.......................37
Standard recirculation ..............................38
Standard non-recirculation.......................38
Recirculation with cross over valve ..........39
Installation w/o recirculation ...................41
X3TM Technology........................................42
Pressure relief valve .................................43
13 Condensate drain ....................................44
14 Electrical connection ...............................45
15 Temperature remote controller ..............46
Installation ................................................46
16 High altitude settings ..............................48
17 Freeze protection system ........................49
18 Easy-Link System .....................................50
Easy link connection procedures ..............51
GETTING STARTED .......................................52
Initial operation ........................................52
OPERATING SAFETY .....................................55
OPERATION ..................................................57
Controller settings ....................................57
Set outlet water temperature...............58
Setting the time ....................................59
Pump operation timers.........................59
Setting pump timers & operation.........60
Selecting a pump timer.........................62
Display example ....................................63
On-demand pump operation................64
Information mode.................................65
Unit of measure conversion..................65
PCB settings ..............................................66
Setting the temperature on the PCB ....66
MAINTENANCE AND SERVICE......................67
Regular maintenance................................67
Measuring inlet gas pressure ...................67
Water filter cleaning.................................68
Rain protection tray cleaning ...................69
How to drain the unit for vacations
or long periods of non-use .......................69
TROUBLESHOOTING.....................................70
ERROR CODE.............................................71
Single unit installation ..........................71
How error codes display
in an Easy-Link System ..........................72
Fault analysis ............................................73
REPAIR PARTS...............................................76
Component diagram.................................76
Parts list ....................................................81
OUTPUT TEMPERATURE CHART ..................82

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.
Installation Manual and
Owner's Guide

SPECIFICATION
4 On-Demand Water Heater Installation Manual and Owner’s Guide
*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.
***Refer to p. 36 for additional information available on pipe lengths.
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.
Model 160X3P
(A/JT-H5JP)
180X3P
(A/JT-H5SP)
199X3P
(A/JT-H5P)
Natural Gas Input
(Operating Range) BTU/h Min: 9,000 Max.: 160,000
Min: 9,000
Max.: 180,000
Min: 9,000
Max.: 199,000
Propane Input
(Operating Range) BTU/h Min: 9,000
Max.: 160,000
Min: 9,000
Max.: 180,000
Min: 9,000
Max.: 199,000
Gas Connection 1/2" NPT
Water Connections 3/4" NPT
Water Pressure* psi (MPa) 15 - 150 (0.1 - 1)
Max. water flow rate GPM (L/min) 6.5 (25) 8.0 (30) 10.0 (38)
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) 68.8 (31.0)
Dimensions
inch H 27.4 x W 17.7 x D 11.2
mm H 696 x W 450 x D 285
Ignition Electronic Ignition
Electric
Supply VAC/Hz 120/60
Consumption
Operation
W/pump W/A 126.7/1.55
W/O pump
Indoor W/A 113.8/1.41
Outdoor W/A 107.0/1.30
Standby W/A 1.2/0.04
Freeze-Protection W/A 129.5/1.10
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)
SPECIFICATIONS

SPECIFICATION
On-Demand Water Heater Installation Manual and Owner’s Guide 5
DIMENSIONS
RETURN 9-3/16 (232.7)
5-13/16 (147)
2-13/16
(72.1)
DRAIN 2-1/4 (56.5)
GAS 5-3/8(136.9)
COLD GAS
DRAINRETURN
PRV HOT 5-15/16 (151.3)
COLD 4-1/2 (115)
HOT 2-3/8 (60.7)
PRV 4-5/8 (116.7)
3-3/8
(85.1) 4-5/8 (118.1)
5-7/16
(137.6) 6 (152)
11-3/4 (298.3)
29-13/16 (756.8)
28-5/8 (727.6)
33-13/16 (858.5)
11-1/4 (285)
27-3/8 (696)
17-11/16 (450)
16 (406.4)
6-1/4 (158.5)
5 (125.8)
9-7/8 (250.8)
Unit: Inch (mm)
φ2.4 (60.9)φ2.4 (60.9)

SAFETY
6 On-Demand Water Heater Installation Manual and Owner’s Guide
1. Follow all local codes, or in the absence of local codes, follow the current edition of the National Fuel Gas Code:
ANSI Z223.1/NFPA 54 in the USA or B149.1 Natural Gas, Propane Installation Code in Canada.
2. Properly ground the unit in accordance with all local codes or in the absence of local codes, with the National
Electrical Codes: ANSI/NFPA 70 in the USA or CSA standard C22.1 Canadian Electrical Code Part 1 in Canada.
3. Carefully plan where you intend to install the water heater. Please ensure:
• Your water heater will have enough combustible air and proper ventilation.
• Locate your heater where water leakage will not damage surrounding areas. (Refer to p. 8.)
4. Check the rating plate for the correct GAS TYPE, GAS PRESSURE, WATER PRESSURE and ELECTRIC RATING.
*If this unit does not match your requirements, do not install and consult with the manufacturer.
5. If any problem should occur, turn off all hot water taps and turn off the gas. Then call a trained technician or the Gas
Company or the manufacturer.
6. The water heater is set only for Natural gas at the factory. If your gas type is LP Gas, gas conversion shall be
required with the included gas conversion kit (100320420) by a qualified installer. (Refer to pp. 11 and 33.)
7. The water heater can be installed outdoors with the outdoor installation kit. (Refer to pp. 11 and 29.)
SAFETY DEFINITION
Indicates information considered important but not hazard related.
NOTICE
Indicates an imminently hazardous situation which, if not avoided, will result in
death or serious injury.
DANGER
Indicates an imminently hazardous situation which, if not avoided, could result
in death or serious injury.
WARNING
Indicates an imminently hazardous situation which, if not avoided, could result
in minor or moderate injury.
CAUTION
WARNING
• Water temperatures over 125°F (52°C) can cause severe burns instantly or death from scalding.
The water temperature is set at 120°F (50°C) from the factory to minimize any scalding risk.
Before bathing or showering, always check the water temperature.
• Do not store or use gasoline or other flammables, vapors, or liquids in the vicinity of this
appliance.
• Do not reverse the water and/or gas connections as this will damage the gas valves and can cause
severe injury or death. Follow the diagram on pp. 38 and 39 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 section on the Freeze
Protection System on p. 49 for more information.
• Failure to observe these warnings could result in severe personal injury or death.
SAFETY GUIDELINES

INTRODUCTION
On-Demand Water Heater Installation Manual and Owner’s Guide 7
INTRODUCTION
• This manual provides information necessary for the
installation, operation, and maintenance of the water
heater. Please read all installation instructions complete-
ly before installing this product. If you have any prob-
lems or questions regarding the installation, operation,
or maintenance, consult the manufacturer or its local
representative.
• This is on-demand, tankless water heater is designed
to efficiently supply hot water when properly sized and
installed.
• This water heater incorporates a recirculation pump.
There are 3 operational modes to choose from:
Recirculation with Dedicated Return line, On-Demand
mode, and Crossover Valve Mode. See page 36 for addi-
tional information.
• These high efficiency models have a built-in secondary
heat exchanger that absorbs latent heat from the exhaust
gas and uses it to increase the efficiency.
• The rating plate lists the model description and is located
on the side of the water heater.
• When the water heater is installed outdoors, attach the
vent cap (100320424) from the manufacturer to the
appliance. (Refer to pp.11, 29, and 30.) Install outdoors
only in areas with mild temperature climate.
6. Water is heated as it circulates through the heat exchang-
ers.
7. Thermistors measure water temperatures throughout the
water heater, the control modulates the gas and water
valves to ensure proper output water temperature.
8. When the tap is turned off, the unit shuts down.
1. A hot water tap is turned on. NOTICE: If recirculation
with dedicated return line configuration is installed, the
recirculation pump activates and the system circulates
water within the loop. Then proceeds to step 3.
2. Water treated by the X3TM Cartridge enters the heater.
3. The water flow sensor detects the water flow.
4. The computer initiates the fan motor, opens the gas
valve, and sends a signal to the igniter to create an igni-
tion spark.
5. The gas ignites and flames appear within the burner
chamber.
*This diagram illustrates tankless water heater design concepts only and does not accurately represent the water
heater’s physical description.
Pressure sensor
Exhaust duct
Primary heat exchanger
Igniter
PCB
Secondary heat exchanger
Exhaust thermistor
Ventury
Orifice
Thermistor
Gas valve
Bypass valve
Thermistor
Water control valve
/Flow sensor
Thermistor
Thermistor
X3TM
Cartridge
Intake Exhaust
Air adjustment valve
Stepping motor
(Combus�on chamber assembly)
Metal knit burner
Cold water
Gas
Hot water
Return line
Condensate
drain port
Recircula�on pump
Hi-limit
Flame rod
Heater
Igniter rod
Gas solenoid valve
Fan motor
Thermo switch
O.H.C.F
TYPICAL OPERATION SEQUENCE

INSTALLATION
8 On-Demand Water Heater Installation Manual and Owner’s Guide
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 have the vent terminal pointing toward any operating window, door, or opening into a
building.
• 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, flammable vapors, corrosive or acid forming chemicals
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 and
pressure 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.
•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 and space heating
applications.
INSTALLATION Step 1: Read this section before you start...
Step 1: Read this section before you start...

INSTALLATION
On-Demand Water Heater Installation Manual and Owner’s Guide 9
INSTALLATION
• WARNING!
• Follow all local codes, or in the absence of local
codes, follow the current edition of the National
Fuel Gas Code: ANSI Z223.1/NFPA 54 in the USA
or B149.1 Natural Gas, Propane Installation Code
in Canada.
• Follow the electrical code requirements of
the local authority having jurisdiction. In the
absence of such requirements, follow the current
edition of the National Electrical Code ANSI/NFPA
70 in the U.S. or the current edition of CSA C22.1
Canadian Electrical Code Part 1 in Canada.
• Failure to do so could result in death, personal
injury, and/or property damage.
• All gas water heaters require correct installation to ensure
safe and efficient operation. This manual must be fol-
lowed exactly. Read the "Safety Guidelines" Section.
• The water heater shall be securely wall-mounted or
mounted on a stand, or installed in the approved recess
box.
• For outdoor installations, locate the water heater in an
open , un-roofed area. Maintain 3 in. (76 mm) minimum
clearance from the left and right sides of the unit. See
"Clearances" on p.12.
• The length of piping between the water heater and fixture
determines the time it takes for the hot water to arrive.
Consider installing the water heater closer to the fixtures,
if the plumbing system allows for it. The water heater
should be the first appliance to access the water line after
utilities water meter.
• Install the water heater in a heated area where below
freezing temperature cannot occur. Units installed in
areas subject to below freezing temperature MUST follow
the steps outlined on p. 49. The warranty does not cover
damage caused by freezing.
• Maintain proper space for servicing. Install the unit so
that it can be connected or removed easily. Refer to the
"Unit clearances" section for proper clearances.
• 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 is 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.
• The water heater must be installed where the proper
amount of combustion air will be available to it at all times
without obstructions. When installed indoors, the water
heater can be direct vented.
• 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 open-
ing to prevent exhaust from entering a building. (Refer to
pp. 10, 26 and 27.) Check local code requirements prior
to installation.
• These units are equipped with a thermistor in the exhaust
system. This component prevents heat damage to ABS,
PVC, CPVC, or polypropylene (Plastic) venting when it is
used. If the exhaust gas temperature exceeds 140°F (60
°C), this component will enable the unit to safely stop
operations.
• If the water heater is used as a direct-vent appliance, the
unit requires 2 in. or 3 in. combustion air supply pipe. The
intake pipe must be sealed airtight. Refer to pp. 14 to 16,
and pp. 21 to 24 for more detail.
• Terminating the venting through a sidewall is recommend-
ed 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 pres-
sure zone allows for pressure balancing, which prevents
nuisance shutdowns.
• The manifold gas pressure is preset at factory and is com-
puter controlled. The pressure should not need adjust-
ment.
• 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.
Step 1: Read this section before you start...

INSTALLATION
10 On-Demand Water Heater Installation Manual and Owner’s Guide
Do not install the heater where water, debris or flamma-
ble vapors may get into the flue terminal. This may cause
damage to the heater and void the warranty.
Prohibited
Do not install the
exhaust vent for
indoor and outdoor
models within 3
ft. (914 mm) of an
overhang. See the
graphic. The area
under an overhang
must be open to
three sides.
Vent termina-
tion must be at
least 2 ft (610
mm) away from
an inside corner
for both out-
door installation
and direct-vent
installation.
USA: 1  (30 cm) min.
Canada: 3  (91 cm) min.
USA: 1  (30 cm) min.
Canada: 3  (91 cm) min.
USA: 1  (30 cm) min.
Canada: 3  (91 cm) min.
USA: 12 in. (30 cm) above grade and
above ancipated snow level
Canada: 12 in. (30 cm) above grade
Ancipated snow level
Ensure that you meet the minimum clearances
shown below for a direct vent termination:
Do not have the vent terminal pointing toward any
opening into a building. Do not locate your heater
in a pit or location where gas and water can accu-
mulate.
Prohibited
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. When direct vented, do not install
the air intake near the dryer vent or any source of
airborne debris.
INSTALLATION
3 ft
(914 mm)
2 ft
(610 mm)
Inside
Corner
Step 1: Read this section before you start...

INSTALLATION
On-Demand Water Heater Installation Manual and Owner’s Guide 11
INSTALLATION
No. Model Indoor Outdoor
1. Temperature remote controller  
2. Pipe cover  
3. Neutralizer kit  
4. Recess box 
5. Outdoor vent cap 
Optional items
Manual Communication
cable X3™ cartridge LP gas conversion kit Pressure relief valve Wall mounting bracket
Screws for
vent ports
Qty: 2
Included items
• Temperature remote controller
100276687 (TM-RE43); Qty:1 See p.42.
• Pipe cover
100320428 (TH-PC05)
The pipe cover protects the piping and X3TM Technology
from environmental factors such as rain, UV rays and
improves the appearance of the installation. The pipe
cover or recess box is recommended when the water
heater is installed outside.
• Neutralizer kit
100112159 (TH-NT01)
Used to raise the pH of the condensate to allow for safe
drainage. (Refer to the Condensate Drain section for
more information.)
• Recess box
New construction: 100321565
Retrofit: 100321749
Recesses the water heater when installed outdoors. The
recess box or pipe cover is recommended when the
water heater is installed outdoors.
• Outdoor vent cap
100320424 (TH-VC05)
The outdoor installation kit consists of a vent top, panel
cover, and junction box. This kit MUST be used when the
water heater is installed outdoors, unless the water heat-
er is installed in a recess box.
Step 2: Familiarize yourself with the components.
Step 2: Familiarize yourself with the components.

INSTALLATION
12 On-Demand Water Heater Installation Manual and Owner’s Guide
INSTALLATION
Installation environment
Warning! Do not store or use flammable
materials, vapors, or liquids in the same location
where this water heater is installed.
Before installing the water heater, ensure that it will be
located as described on p. 8 through 10. In addition to that,
the following factors shall be taken into account for the
installation location and method. Refer to each section in
the installation manual.
Atmosphere temperature
Install the water heater in a heated area where below
freezing temperature cannot occur. Units installed in areas
subject to below freezing temperature MUST follow the
steps outlined on p. 49. The pipe cover or recess box is
recommended when the water heater is installed outdoors
because it provides better protection from the elements.
Combustion air supply
The water heater requires fresh combustion air should be
free of corrosive elements and flammable vapors. If it is
installed at the contaminated area or in a confined area,
direct venting installation is recommended. (Refer to pp. 17
to 25.)
Proper ventilation
For proper operation the water heater must be vented in
accordance with the section “Venting of Equipment” of the
current edition of the National Fuel Gas Code: ANSI Z223.1/
NFPA 54 in the United States and/or Section 8 of the B149.1
Natural Gas and Propane Installation Code in Canada, as well
as applicable local building codes. (Refer to pp. 14 to 30.)
Proper mounting and clearance
The water heater shall be securely mounted on wall that
can support the weight of the water heater. A wall mounting
bracket is supplied with the water heater to securely mount
the water heater to wall studs. (Refer to p. 13.) The water
lines, gas line, condensate drain line, and pressure relief
valve discharge line shall be supported using field supplied
pipe hangers. The water heater shall not bear the weight of
these lines. The water heater requires proper installation
clearance for operation and service as described in the right.
Condensate Drain line
The condensate produced is acidic. Drain the condensate in
accordance with all local codes and common safety practic-
es. (Refer to p. 44.)
Unit clearances
Warning! 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.
Indoor
Top:
12 in (305 mm)
Front:
4 in (102 mm)*
Back:
0.5 in (13 mm)
Side
3 in (76 mm)
Bottom:
18 in (458 mm)
*24 inches (610 mm) recommended for maintenance.
Outdoor
Top:
36 in (914 mm)
Front:
24 in (610 mm)
Back:
0.5 in (13 mm)
Side
3 in (76 mm)
Bottom:
18 in (458 mm)
Step 3: Installation environments and unit clearances
Step 3: Installation environment and unit clearances

INSTALLATION
On-Demand Water Heater Installation Manual and Owner’s Guide 13
INSTALLATION
1. Secure the wall mounting bracket with 4 screws to
the wall studs. Make sure to level the bracket.
Wall Stud Wall Stud
16” (406.4 mm)
Drywall cut away to
show proper method
to mount the bracket
to the wall studs.
2. Hang the water heater bracket on the wall bracket.
3. Secure the water heater firmly fastening
appropriate screws into the upper bracket/bottom
brackets of the water heater and wall.
Step 4: Mounting the water heater
Step 4: Mounting the water heater

INSTALLATION
14 On-Demand Water Heater Installation Manual and Owner’s Guide
INSTALLATION
The Indoor model must be vented in accordance with the section “Venting of Equipment” of the current edition of
the National Fuel Gas Code: ANSI Z223.1/NFPA 54 in the United States and/or Section 8 of the B149.1 Natural Gas
and Propane Installation Code in Canada, as well as applicable local building codes.
The use of venting materials approved for Category III/IV appliances is recommended whenever possible. However,
the Indoor model may also be vented with plastic 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) Section on
p. 20. Vent installations in Canada which utilize plastic vent systems must use venting that complies with ULC S636.
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, 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 inspection of the unit.
• The water heater vent must not be connected 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. Regarding exhaust pipe, refer to pp. 22 to 24.
• 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.
• 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.
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 pp. 26 to 28.
Step 5: General instructions of venting
Step 5: General instructions of venting
• 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

INSTALLATION
On-Demand Water Heater Installation Manual and Owner’s Guide 15
INSTALLATION Step 5: General instructions of venting
How to install venting into the water heater
WARNING
• When inserting the pipe into the exhaust/intake port, make sure that the pipe end is cut
straight and positioned properly under the o-ring to seal the connection firmly.
• 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.
1. Insert 2" straight pipe fully into the exhaust/intake ports. (Figure 1) The pipes should
insert 2 inches.
WARNING: The exhaust vent pipe connection to the water heater must be flush to
maintain a proper seal. Check pipe for a 90° edge before installation. DO NOT use a
field cut end for the connection. Failure to follow can cause carbon monoxide poisoning
or death.
2. Use a screwdriver to tighten the clamp. (Figure 2)
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. (Figure 3)
For 3" Vent Installs: Insert 2" straight pipe, up to 1 ft max. length, into the heater exhaust/intake ports.
WARNING: The exhaust vent pipe connection to the water heater must be flush to maintain a proper seal.
Check pipe for a 90° edge before installation. DO NOT use a field cut end for the connection. Failure to follow can
cause carbon monoxide poisoning or death.
Install a 2" x 3" increaser to convert to 3" venting. For low clearance installations, a 2" long sweep elbow may be
used. Then 1 ft max length straight pipe may be used to fit 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” to 3”
Adapter
Power Vent (PV)
2” Pipe
3” Pipe
2” to 3”
Adapter
2” Pipe 2” Pipe
Direct Vent (DV)
2” Pipe
2” Pipe
3” Pipe
Pipe end
not flush
with base.
Pipe end
is flush
with base.
Figure 1
90° edge
Not a 90° edge
Exhaust Vent
Pipe
Exhaust Vent
Pipe
Intake Port
Exhaust
Port
Intake Port
Exhaust
Port
Intake Port
Exhaust
Port
Intake Port
Exhaust Port
Figure 2
Figure 3

INSTALLATION
16 On-Demand Water Heater Installation Manual and Owner’s Guide
DIP switches
(Default)
Vent
style Vent type Vent length
Lower
bank
of DIP
switches
1 2 3 4 5 6 7 8
ON
No. 3: ON
No. 4: OFF
2" DV Intake 10 to 60 ft (3.1 to 18.3 m)
Exhaust
2" PV Intake 2" elbow: 5 ft (1.5 m)
Exhaust 15 to 60 ft (4.6 to 18.3 m)
3" DV Intake 60 to 150 ft (18.3 to 45.7 m)
Exhaust
3" PV Intake 2" elbow: 5 ft (1.5 m)
Exhaust 60 to 150 ft (18.3 to 45.7 m)
DIP switches Vent
style Vent type Vent length
Lower
bank
of DIP
switches
1 2 3 4 5 6 7 8
ON
No. 3: OFF
No. 4: ON
2" DV Intake 5 to 9.9 ft (1.5 to 3.0 m)
Exhaust
2" PV Intake 2" elbow: 5 ft (1.5 m)
Exhaust 5 to 14.9 ft (1.5 to 4.5 m)
3" DV Intake 5 to 59.9 ft (1.5 to 18.3 m)
Exhaust
3" PV Intake 2" elbow: 5 ft (1.5 m)
Exhaust 5 to 59.9 ft (1.5 to 18.3 m)
Outdoor installation (Refer to p.29.)
Changing DIP switch
1. Remove the front cover.
2. Pull out the PCB.
3. Locate the lower bank of the DIP switches.
4. Change the DIP switch.
DIP switch settings for the vent style
Set the DIP switch as shown in the following for your vent style. If your vent style is out of the range of the upper
table, change the DIP switches as shown in the lower table. WARNING! Before changing the DIP switches, make
sure that there is no power supply, gas supply, and water supply.
INSTALLATION Step 5: General instructions of venting

INSTALLATION
On-Demand Water Heater Installation Manual and Owner’s Guide 17
• The guidelines in this section apply to installations within the United States. All U.S. installa-
tions must conform to the National Fuel Gas Code, ANSI Z223.1/NFPA 54 (current edition) and
local codes.
• Canadian requirements differ from the guidelines in this section. In Canada, follow the
requirements of B149.1 (Natural Gas and Propane Installation Code, current edition) as well as
local and provincial codes. Contact your local code enforcement agency for direction.
NOTICE
This gas water heater requires an adequate source of clean air for combustion and ventilation.
Without sufficient air, your water heater may not operate properly and may emit excessive and
abnormal amounts of carbon monoxide which may result in carbon monoxide poisoning or
death.
WARNING
Before installing the water heater, you must determine the amount of air needed to supply this water heater and
any other gas appliances in the same area and provide adequate air for combustion and ventilation. Consult a qual-
ified person if you’re unsure of the proper way to supply air to your water heater.
Check for Chemicals:
Air for combustion and ventilation must be clean and free of corrosive chemicals. If corrosive chemicals, such as
sulfur, flourine, or chlorine are present, the water heater must be direct vented. Failure due to these corrosive
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. Examples of locations that require outside air due
to chemicals include:
• Beauty salons
• Photo processing labs
• Indoor pools
• 
• 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.
Does your installation space have sufficient combustion air?
Ventilation with outside air is recommended for all installations. 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 tightly sealed and often
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 ventilation. If you are unsure if your installation location has enough ventila-
tion, contact your local gas utility company or code officials for a safety inspection or direct vent the water heater
The following instructions will help determine if it may be possible to install the water heater without outside venti-
lation.

To calculate the combustion air and ventilation required, add up the total BTU/h ratings of all gas burning applianc-
es (e.g., water heaters, furnaces, clothes dryers) in the same area. Do not include appliances that are direct vented.
Refer to the following example.
INSTALLATION
Step 6: Combustion air supply
Step 6: Combustion air supply

INSTALLATION
18 On-Demand Water Heater Installation Manual and Owner’s Guide
Your water heater’s BTU/h rating is on the rating plate. The BTU/h ratings should be on the other appliances’
rating plates. If you have trouble determining the BTU/h ratings, contact the manufacturer or have a qualified
person determine the ventilation requirements.
NOTICE: If you are replacing your old water heater with one that has a higher BTU/h rating, the amount of ventila-
tion required may be greater.
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.
Room Volume (ft3) = Floor Area (ft2) X Ceiling Height (ft)
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 better estimate of the air available.
Air Volume = Room Volume - Object Volume
NOTE: Adjoining rooms with permanently opened doorways can be counted as part of the calculation.
Calculate required air volume
A water heater installed in an unconfined attic, garage, or space requires that the space be at least 50 ft3(1.42 m3)
per 1,000 BTU/h of the total input for all gas burning appliances in the same area.
Required Air Volume (ft3) =Total Appliance Energy Rating (btu/h) X 50 ft3/ 1000 (btu/h)
Example:
(294,000 x 50) / 1000 = 14,700 ft3
If the air volume of the room is less than the required air volume, you must direct vent the water heater or provide
permanent outside air openings that draw in sufficient air. Go to “Install with outside ventilation” if you want to
provide combustion air with outside ventilation.
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 ventilation. However, be sure to consider the effects of exhaust fans.
Exhaust fans can affect the amount of combustion air that is available in your home. Appliances such as furnaces,
whole house fans, and clothes dryers draw air out of your home. If they draw air out faster than it can be replaced,
your water heater may not have enough oxygen to fire properly. Back-drafting may also result, which is when neg-
ative air pressure pulls air backwards through chimneys or appliance vents. These events can cause unsatisfactory
water heater performance. The best solution is to direct vent the water heater or install an adequate number of
make-up air vents. (See “Install with outside ventilation”.) For more information, consult a qualified technician or
your local gas utility.
Install with outside ventilation
Ventilation with outside air is recommended, and, for most installations, is needed. There may be existing ventila-
tion that is adequate, or you may need to add more ventilation.
Supplying outside air to the water heater typically requires two openings. One opening must be within 12 in (305
mm) from the floor and the second opening must be within 12 in (305 mm) 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 1. Two openings must be used when ventilating with air from another room.
The outside air can be taken from a crawl space or attic open to the outdoors and adequately ventilated. You may
use vertical or horizontal ducts.
INSTALLATION Step 6: Combustion air supply

INSTALLATION
On-Demand Water Heater Installation Manual and Owner’s Guide 19
Determine type of ventilation
There are several types of ventilation that can be used. The various options are listed below. See also the illustra-
tions on the next page.
1. Direct to outdoors (See Figures 1&2)
2. 
3. Horizontal ducts (See Figure 4)
4. Single opening (not recommended; must be at least 100 in2(645 cm2
3(1.42 m3
5. From a larger room inside the house (not recommended – refer to "Calculate the air volume of the room" on page 18 to
determine if the combined volume of the rooms may be adequate).
Determine minimum free area required for each vent opening
The size of the vent openings depends on the total BTU/h rating of all appliances in the space (use your calculation
from “Before beginning”) and the type of vent used. Table 1 provides the minimum free area for each vent opening
depending on the type of ventilation.
Calculate minimum size of vent openings and ducts
The vent cross-sectional area needed to provide the free area depends on the covering on the vent openings.
Typical vents use louvers or grilles to protect the opening. The louver or grill itself blocks some of the free area, so
the opening may need to be larger to meet the minimum free area requirements.
Use the following formula to calculate the required cross-sectional area:

2(645 cm2) of free area would need 134 in2(865
cm222).

• 
• 

• 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
-

chlorine. Be sure that air at the vent inlets is free of such chemicals.
See graphics on next page.
Table 1


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)



INSTALLATION Step 6: Combustion air supply

INSTALLATION
20 On-Demand Water Heater Installation Manual and Owner’s Guide
Combustion air supply options
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 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
INSTALLATION Step 6: Combustion air supply