American Hometec AHG-T42-NG User manual

Gas Tankless Water Heater
Installation and Operation Manual
Model AHG-T42
American Hometec, Inc.
3411 Silverside Road
Hanby Building
Wilmington, DE 19810
WARNING: If the information in these instructions is not followed exactly, a fire or
explosion may result causing property damage, personal injury or death.
- 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 electrical switch; do not use any phone in your building.
•Immediately call your gas supplier from a neighbor’s phone.
•Follow the gas supplier’s 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.
- Water heater for other than recreational vehicle installation only.
www.AmericanHometec.com
[e-mail]
Toll Free: 1 - 800 - 295 - 8039

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Contents
INTRODUCTION AND SAFETY WARNINGS
INTRODUCTION 3
IMPORTANT SAFETY INSTRUCTIONS 3
SAFETY WARNINGS 4
OPERATION
DESCRIPTION OF OPERATION 6
OPERATING INSTRUCTIONS 7
EXTENDED SHUTDOWNS 13
COLD WEATHER WARNINGS 15
MAINTENANCE AND INSPECTION 16
TROUBLESHOOTING 19
DIAGNOSTIC CODES 22
INSTALLATION
INSTALLATION GUIDELINES 25
PACKING LIST 26
LOCATION AND CLEARANCE REQUIREMENTS 27
TYPICAL INSTALLATION 27
MOUNTING 28
ELECTRICAL 29
GAS PIPING 32
WATER PIPING 33
AIR INTAKE AND EXHAUST (VENT) SYSTEM 34
START UP AND TESTING 41
REFERENCE
WIRING DIAGRAM 43
SYSTEM SPECIFICATIONS 45
DIMENISIONS 46
NAMES OF MAJOR PARTS AND COMPONENTS 46
SPARE PARTS 47
LIMITED WARRANTY 49
IMPORTANT: KEEP THIS MANUAL FOR FUTURE REFERENCE!

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INTRODUCTION AND SAFETY WARNINGS
INTRODUCTION
Thank you for purchasing an American Hometec
™
Gas Tankless Water Heater. In
order to ensure proper installation, safe operation, and long life, please carefully read
these instructions. Installation should only be completed by licensed professionals.
Theuse of professionals ensures the installation is in full compliance with all
required building, plumbing and electrical codes.
KEEP THIS MANUAL for future reference. This booklet includes useful information
about the product, maintenance requirements and the details of your product
warranty.
IMPORTANT SAFETY INSTRUCTIONS
READ AND FOLLOW ALL INSTRUCTIONS.
When using this equipment, basic precautions should always be followed.
Safety Definitions
This symbol is the safety alert symbol which is used to alert you to potential hazards
that can kill or hurt you and/or others.
Indicates an imminently hazardous situation which if
not avoided will result in death or serious injury.
Indicates a potentially hazardous situation which if
not avoided could result in death or serious injury.
Indicates a potentially hazardous situation which if
not avoided could result in minor or moderate
injury. It may also be used to alert against unsafe
practices.

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SAFETY WARNINGS
DO NOT use a fuel gas that is not listed on the nameplate as compatible
with the water heater. Abnormal combustion or a deflagration may occur
which can cause a serious accident
DO NOT use the unit if the vent piping has been damaged or altered in any
way including cracking, separation, rusting, melting, etc. Improper venting
may cause a buildup of Carbon Monoxide (CO) which can cause brain
damage or death.
If the water heater needs to be installed, moved, or serviced only utilize licensed
professionals. The use of professionals ensures all work is in full compliance with
required building, plumbing and electrical codes.
Keep the area around the appliance clear and free of flammable materials such as cloth,
wood, aerosol cans, paper, gasoline, etc.
When using hot water for a shower or bath always check the water temperature before
entry to avoid being scalded. Obey local codes for the maximum water temperature setting
allowed. Water temperatures over 125oF (52oC) can cause severe burns or death from
scalds. Households with small children, disabled or elderly persons may require a setting
of 120oF (49oC) or lower.
This heater is designed only for the heating of water and should not be used for other
applications or used to heat any other media.
Never use a fuel gas that is not listed on the nameplate as compatible with the water
heater. Abnormal combustion or a deflagration may occur which can cause a serious
accident including damage to the heater.
Do not use this appliance if any part has been under water. Consult a qualified service
technician to inspect the appliance and make any required repairs prior to installation and
operation.
This water heater is designed for indoor mounting. Never mount it outdoors.
This equipment should be installed in an area where water leakage from the unit or
connections will not result in damage. The manufacturer is not responsible for any
damages resulting from leaks.
Only connect gas and water as instructed. Incorrect or reversed connections will cause
equipment damage.
Do not over tighten connections or equipment may be damaged.
Do not install in areas that are subject to vibration.

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This equipment may not be operated without the vent pipe properly connected. The
exhaust pipe must not terminate in an area where the exhausting vapor or collecting
condensate could create a hazardous situation or cause property damage. Exhaust gases
must be vented out of the building in compliance with all building codes.
The exhaust piping is very hot during and for a period after use. Do not touch the pipe.
Ensure that snow, ice or other debris does not block the inlet or exhaust pipes.
Regular housekeeping should be done in areas around the heaters to prevent insect
intrusion and possible equipment malfunction.
The unit should be serviced on a routine basis to ensure optimum performance. Service
needs will vary based on local water conditions including acidity, alkalinity, hardness, etc.
Freezing temperatures will cause damage to the heater. Install in locations where freezing
temperatures are not reached and follow procedures to drain the unit if it will be out of
service for a period of time.
A 120 V / 60 Hz power source should be used. Fire, electrical shock or damage to the water
heater may occur if an incorrect power supply is used.
This appliance is equipped with a three-prong grounded plug for increased protection
against electrical shock. Ensure the plug is properly inserted into a clean, dry outlet that
complies with all electrical codes. Only insert and remove the plug using the plug head and
never use a wet hand to plug or unplug the power plug.
Any alterations to the appliance will void the warranty.

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OPERATION
DESCRIPTION OF OPERATION
oAmerican Hometec gas tankless water heaters provide an efficient reliable supply of hot
water.
oThe temperature can be adjusted between 95oF and 149oF (35oC - 65oC).
oOnly a small amount of water and a low water pressure (15psi) are required for the unit. Unit
requires 0.67 gpm (2.5 l/min) to enable the unit. Unit stays in operation until the flow drops
below 0.53 gpm (2 l/min).
oThe burner ignition is electronic. The unit has no pilot light and consumes no gas when the
heater is not being used.
oAir is brought into the unit from outside, efficiently burned with the appropriate source of fuel
and then exhausted externally.
oThe unit’s integrated control system constantly monitors the temperature of the water being
produced and adjusts the burner accordingly to deliver a stable supply of hot water.
oThe unit is highly flexible and provides hot water over a wide range of flow rates and incoming
water temperatures across the capacity range of the unit.
oAmerican Hometec heaters include convenient H2O Saver Technology™, a digital functionality
that allows owners to control hot water consumption and conserve water.
oMultiple protective functions are included such as no-load heating prevention, automatic
shutdown in case of accidental flameout, automatic pressure relief, etc. to make the appliance
both safe and reliable
oIn the event of a disruption in operation, a failure code is displayed and an alarm sounds an
alert.

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OPERATING INSTRUCTIONS
Normal Operation
This section of the manual instructs an owner on routine operating procedures and assumes that
the water heater has already been installed, tested, and approved for operation. Initial start up
requirements is detailed in the “Installation” section of this manual.
Routine Start Up
Follow this procedure for a heater that has been out of service.
1. Ensure all drain plugs are installed in unit.
2. Ensure all hot water use points (faucets, etc) are closed.
3. Open the water inlet valve.
4. Open a hot water faucet to confirm water flow and then close the faucet.
5. Open the fuel gas valve.
6. Plug in the unit.
7. Press the “ON/OFF” key to turn on the
unit. The message “CL” will be displayed
indicating “Cold” state.
8. Set temperature (see “Temperature
Control” section of this manual)
Control Panel
The Control Panel and display are used to adjust the operational settings of the unit as well as give
information about the current state of operation. The following illustration shows all possible
symbols and signs that may appear in various states of operation. In operation only the symbol or
sign corresponding to the actual state will appear on the control panel display. The water heater is
in an operating state when the hot water temperature is shown.
Figure 1 - Start Up

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CONTROL PANEL INDICATIONS
LED display
1. Indicates the “Temperature Set Point” when blinking. Displays the “Actual Temperature”
when the display remains lit.
2. It displays both the “Preset Water Quantity” and the “Actual Water Quantity”.
“Combustion” - When lit indicates that the water heater is operating and burning gas.
“Water valve” - Indicates one of the following three states:
1. No light indicates water heater is operating normally.
2. Blinking: Indicates there is no water flow through the water heater or the water flow is less
than 0.66 gallons per minute (2.5 liters per minute)
3. When on and remaining lit, the firepower of the water heater is operating at either the
minimum or maximum operating point. The actual water temperature may not reach the
preset temperature. The water flow rate needs to be adjusted so the unit is operating
within its capacity range. This will allow the desired temperature to be reached.
“oC/L” - Indicates metric units are being displayed (degrees Celsius, liters)
“oF/G” - Indicates English units are being displayed (degrees Fahrenheit, gallons)
“Up + / Down -” keys - Used for setting the water temperature and water quantity.
“Mode” key - Used to Set (F4) the water quantity or Display (F3) the water volume already
delivered.
“OFF/ON” key: This button enables or disables the water heater. In the “ON” mode, the
temperature set point is displayed. The factory default temperature setting is 107oF (42oC). In
the “OFF” mode, “CL” (Cold) is displayed.
Figure 2 - Control Panel Diagram
When the water temperature is above
95° F (35° C) the lamps are lit one
by one from bottom to top.
Failure mode displays when a failure
occurs, temperature display mode is
switched to failure display mode.
Description of the mode key
F3 current water quantity
F4 preset water quantity

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TEMPERATURE CONTROL
Set the Desired Temperature
1. The temperature adjustment range is 95oF - 149oF (35oC –65oC)
2. Press the “OFF/ON” key. The temperature display unit lights up and displays the current
temperature set point. The factory default set point is 107oF (42oC).
3. Press the “UP” or “DOWN” key to set any desired temperature between 95oF (35oC) and
122oF (50oC). The temperature set point goes up or down by one degree with each press.
4. To set a temperature above 122 oF (50oC): Press and hold the “UP” key continuously for
about 4 seconds until 131oF (55oC) is displayed.
5. Note: When the temperature is above 122 oF (50 oC), each press of the “UP (DOWN)” key
causes the temperature to go up (down) by 5 oC (9oF).
6. When the desired temperature is set above 122oF (50 oC), the temperature display blinks
for approximately 4 seconds before the display switches to show actual water temperature.
7. Along the left side of the temperature display, a series of bars indicates the level of the
temperature set point. At each 5 oC (9oF) increment, an additional bar lights. When the set
point is above 122oF (50 oC), the first red bar appears indicating the set point is in a zone
where a scalding hazard exists.
8. The heater will retain the temperature set point unless there is a loss of power.
9. After the temperature is set, open the water valve and observe. The “Combustion”
indicator should light indicating the unit is operating normally.
SCALD PREVENTION
oWater temperatures over 125oF will scald and can
instantly cause severe burns or death!
oChildren, disabled and elderly are at highest risk of
being scalded
oAlways test the water temperature by feeling the water
prior to entering a shower, bath, etc.
oObey all codes regarding temperature set point.
Contact a licensed plumber or local plumbing authority
for clarification or additional information.

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H2O SAVER TECHNOLOGY™ - Set a Desired Volume
1. The volume display range is 0-250 gallons when system is set to use English
units or 0-950 liters when in metric mode.
2. Press the “MODE” key briefly to display the message “F4”, then press the “UP”
( or “DOWN”) key. The mode will switch from temperature display mode to
water quantity display mode.
3. Displayed volume: Please note that the readout indicates the water quantity divided by ten
(10). Example –if the display shows “10”, this correlates to a volume of 10x10 = 100 gallons
(English unit mode) or 100 liters (metric unit mode).
4. Adjust the “Volume Set Point” by pressing the “UP” or “DOWN” key briefly. Each press
corresponds to a change of 10 gallons of volume (English unit mode) or a change of 50 liter
(metric mode).
Example 1: English unit mode: The digit 7 is currently being displayed. This indicates a set
point of 70 gallons. Pressing the “UP” key once changes the set point to “8” indicating a
water quantity of 8×10 = 80 gallons as the new set point.
Example 2: Metric unit mode: The digit 25 is displayed. This indicates a set point of 250
liters. Pressing the “UP” key once changes the display to “30” indicating a water quantity of
30x10 = 300 liters as the new set point.
5. When the water heater is discharging water to the bathtub and the volume set point is
reached, the alarm on the remote controller will sound an alert for about 10 seconds.
Note: The output of hot water will not stop automatically.
IMPORTANT! The volume measurement only keeps track of the water
volume that passes through the water heater. For example, if hot water
going to a tub is combined with cold water, the volume computed would not be representative of
the total amount that may have filled the tub. This could lead to an overflow or damage!
Monitoring the Volume Delivered
Press the “MODE” key. The message “F3” will be displayed. Press the “UP” (or DOWN) key
briefly. The mode will switch from temperature display mode to water quantity display mode.
The water volume already delivered is displayed. Example: “5” = 5×10 (50L or 50G).
Power Outage
In the event of a power outage or if the unit is unplugged, settings are restored to their factory
default values.

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WIRED REMOTE CONTROL PANEL
The heater may be controlled by a wired remote control (optional). The controller can be located
near a bath, shower or other location.
Remote Control Panel Indications
“Combustion” - When lit indicates that the water heater is operating and burning gas.
“Override” - When this indicator light is on. The wired control panel can change the temperature
set point.
“oC/L” - Indicates metric units are being displayed (degrees Celsius, liters)
“oF/G” - Indicates English units are being displayed (degrees Fahrenheit, gallons)
Remote Control Panel Functions
Remote shut down: If the water heater needs to be stopped when it is operating, press the
“OFF/ON” key. The displayed hot water temperature disappears. The water heater has
stopped operating. The “Combustion” indicating light will go out. The water flow is not
controlled by the remote. The water flow will continue until the faucet or shower is turned
off.
Switch between metric and English units: Press and hold the “Temperature up” and
“Temperature down” keys at the same time for about three seconds.
Override (Priority) Control: Up to three remote control panels may be connected to the
system. At any given time, one of the control panels can become the “priority” controller.
The priority controller becomes the master temperature control device for the system. To
set priority:
Figure 3 - Wired Remote Control Panel

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1. Turn off the override if it is set on another controller. Press and hold the
“Override” key to release priority. The Override indicator light will go out.
2. Select the new controller to take control. Press and hold the “Override” key on the
wired operation panel which should have priority. The “Override” indicator will
turn on and the temperature set point may be adjusted from this controller.
Another way to gain priority is to press the “ON/OFF” key twice on the units
operation panel. The first press will shut the unit off, which will invalidate the
Override ownership of the remote, and the second press will reactivate the unit
which will reinstall factory defaults and set the unit’s panel the Override position,
the “Override” indicator will turn on. When unit is in standby, the first wired
controller to activate the unit will have priority and the Override indicator will turn
on.
Change the Temperature Set Point: First, enable “Override” or priority control for this
remote control. Adjust the temperature using the “Up” and “Down” arrows.
The temperature may be adjusted in one degree increments between 95oF (35oC) and
122oF (50oC).

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EXTENDED SHUTDOWN
Extended Outage Procedure
If a heater will be out of service for an extended amount of time, use the following procedure to
protect the unit.
NOTES
Cold air may enter the unit through the air intake or the exhaust system. Take precaution
for extended shutdowns even if unit is installed indoors in an area that does not allow
direct exposure to freezing temperatures.
Temperatures at or below 32oF (0oC) can cause permanent damage the unit and/or the
piping system due to freezing.
After a power outage, all settings return to their factory default values.
The heater and water within the unit may be very hot. Allow time for the
system to cool and use caution when draining to minimize risk of injury.
1. Shut down the water heater by pressing the “ON/OFF” button. “CL” will appear indicating
“Cold” state.
2. Close the fuel gas valve (1).
3. Unplug the power cord (3). Use dry hands. Exercise
caution and only unplug by grasping the plug head and
pulling. Note, all factory settings will be restored next
time unit is re-powered.
4. Close the water inlet valve. (4)
5. Open all hot water faucets.
6. Obtain an appropriate container to collect the residual water from the system.
Prevent water from being discharged on the floor to avoid damage.
Prevent water contact with any electrical source in the vicinity.

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7. Open the drain plugs and completely drain the water heater.
8. Continue draining to empty the whole hot water system.
Note: Freezing temperatures below 32oF (0oC) can cause permanent damage to the heater
and/or the piping system.
9. Reinstall the drain plugs and close the hot water faucets.
10. To return a unit to operation, please refer to “Routine Start Up” found in the Operating
Instructions section of this manual.
Figure 4 - Drain plug location

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COLD WEATHER WARNINGS
Freezing Damage Potential and Precautions
Freezing temperatures can damage the water heater and/or water piping. Freezing water expands
rapidly and can create tremendous mechanical forces. Mechanical damage and pipe ruptures can
result from only brief exposure to freezing temperatures.
For best results, completely shut down the system by following the Extended Outage Procedure
section of this manual.
In cold regions, insulating material or heat tracing can be used to protect pipes and fittings. Please
consult your dealer if necessary.
Cold Weather with Potential Freezing Temperatures
Keep water flowing through the system to guard against freezing.
Follow these steps:
1. Close the fuel gas valve.
2. Turn off the power by pressing the “ON/OFF” button. “CL” will be displayed when off.
3. Open the hot water faucet at one or more points of use (sink, upstairs bathtub, etc.)
Maintain a constant trickle. Monitor the stream of water to ensure it is still flowing.
No Flow Due to Expected Frozen Heater
1. Close both the fuel gas valve and the water inlet valve.
2. Turn off the power switch.
3. Open a hot water faucet.
4. Open the water inlet valve now and then to check for a water flow.
5. If no flow, attempt to thaw heater by using a portable heat source such as a hair dryer or
portable electric heater.
6. Check occasionally to see if water flow has started.
7. When water flow resumes, carefully check for any signs of water leakage.
8. Resume normal operation
To prevent damage, NEVER force a heater to operate while in a frozen
state. NEVER bypass any safety feature.
Warranty
Damage caused by freezing is NOT covered by Warranty.

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MAINTENANCE AND INSPECTION
Routine Inspection
The heater and exhaust piping will be hot during and shortly after use. Use
caution when working in the area around the heater.
To keep your water heater operating optimally please refer to the below recommended inspection
and maintenance checklists. American Hometec recommends a periodic inspection performed by
a qualified service technician. An annual inspection is normally sufficient. Frequent visual
inspections by the owner are also recommended. Any repairs should be performed by a qualified
service technician using only factory authorized components. Contact American Hometec at 1-
800-295-8039 or see www.americanhometec.com for assistance in locating a qualified technician.
Routine Inspection Checklist
Any flammable materials in the vicinity of the water heater or exhaust piping?
Any unusual noises coming from the heater while in operation?
Are the air intake and exhaust free from any blockage or foreign objects?
Any signs of water leaking near heater or pipes?
Any abnormal appearance to unit casing?
Any Discharge from Relief Valve?
Maintenance Checklist
Clean outside of unit and control panel
oUse a wet cloth to remove any surface dirt. Use a dry cloth to wipe it dry.
oA very mild detergent may be used if unit is very dirty.
oNever use any petroleum based cleaners or solvents. These solvents can damage
the panel.
Check and clear Air Intake of any debris that might impede air flow.
Clean inlet water screen
Examine venting system to insure system is clear of blockages, debris, and damage.
Clean inside of unit by vacuuming or blowing out dust that collects in the unit. The burner
and heat exchange are sealed units and should not be opened.
Visual flame inspection

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Lime scale cleaning (if required), See procedure in Maintenance Procedures that follow.
MAINTENANCE PROCEDURES
BURNER INSPECTION AND CLEANING
1. The burner must flame evenly over the entire surface of the burner head when operating
correctly.
2. The flame should burn with a clear, blue, stable flame.
3. Presence of a yellow flame or of black deposits on the burner head indicates cleaning
and/or burner replacement should occur. THIS MUST BE DONE BY A TRAINED SERVICE
PROFESSIONAL ONLY.
BLOWER MOTOR MAINTENANCE
1. The Blower Motor is permanently lubricated and does not need periodic lubrication.
2. If Blower Motor fails it should only be replaced by trained service professionals only.
RELIEF VALVE DISCHARGE
If a relief valve discharges periodically, this may be due to thermal expansion in a closed water
supply system. Contact the water supplier or local plumbing inspector on how to correct this
situation. Do not plug the relief valve.
LIME SCALE CLEANING PROCEDURE
Materials required:
oFive gallon container
oFour gallons of virgin food grade white vinegar or virgin food grade citric acid
oSmall inline recirculation pump capable of circulating 2 - 4 gpm (8 –16 l/m)
oSet of hoses for connecting recirculation pump to and from the pump and the five gallon
container.
Refer to the figure on following page while performing this procedure.
1. Disconnect electrical power to the water heater.
2. Close the shutoff valves V3 and V4 on both the hot water and cold water lines
3. Connect a hose H1 form the pump outlet to the cold water line V2 into the
heater.
4. Connect drain hose H2 from the hot water outlet line V1 and route into five
gallon recirculation container.
5. Pour approx. four (4) gallons of virgin, food grade, white vinegar or citric acid
into pail.
6. Place the pump suction hose H2 into the cleaning solution

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7. Open valves V1 and V2 into the water heater.
8. Operate the pump. Circulate the cleaning solution through the water heater for at least 45
minutes.
9. Turn off the pump.
10. Rinse the cleaning solution from the water heater by closing valve V2 and opening valve V4,
flow water through the heater and into a container or drain for at least five minutes.
11. Close Valve V1 and Open Valve V3 this places the house back online.
12. Disconnect all hoses.
13. It is also wise to clean the water inlet screen at this time. Close Valve V3 and V4 to do so.
Clean the water inlet screen and remove any debris.
14. Replace the screen and open valves V3 and V4 once more. Checks for leaks.
15. Return heater to operation by following start up instructions.
ELECTRICAL MAINTENANCE WARNINGS
Label all wires prior to disconnection when serving controls. Wiring errors
can cause improper and dangerous operation. Always verify proper
operation after servicing.

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T ROUBLESHOOTING
For operating difficulties with your unit, please consult he following table for guidance. If you
need further assistance, call American Hometec, Inc. toll free service and support line at
1-800-295-8039. Please have product information ready when you call including serial
number, date of purchase and error code if shown on the control panel.
Note: Please check water heater for an error code and respond according to recommendations
found in “Error Codes” portion of this manual.
Trouble
Possible Cause
Remedy
No power: Power
indicator lamp is not lit
Power outage
Unit requires 120V power. Use unit when
power is restored.
Check circuit breaker and reset if needed.
Check ground fault circuit interrupter (GFCI)
if circuit includes one and reset if necessary.
Unit is unplugged
Check power plug and ensure properly
plugged.
Plug the power plug properly.
There is no hot water
flow when a hot water
faucet is opened.
No/empty fuel source
Water valve closed
Power outage
Flow is too low or became
too low. (less than 0.66
gallons per minute (gpm) or
2.5 liters per minute (l/m)
Freezing temperatures may
have frozen water in the
heater or hot water system.
Fuel gas meter special
control restrictions
Distance from heater to
source is long
Fuel gas valve needs to be open
Refill source tank (if applicable)
Open the water inlet valve.
Unit requires 120V power to operate.
Flow is below the lower limit necessary for
stable burner operation and proper
temperature control. Increase the hot water
flow to enable system.
See “No Flow Due to Expected Frozen
Heater” section of this manual for procedure
to thaw unit.
Some fuel gas valves may have special
restrictions or digital controls that use.
Consult your gas supplier and/or a service
professional for assistance.
Allow time for hot water to travel through
system to reach the point of use.

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Trouble
Possible Cause
Remedy
Hot water is not the
right temperature
(too hot or too cold)
Temperature set point was
reset due to power outage.
Temperature set point
incorrect.
Flow is beyond capacity
Incoming water is too warm
Power outage restores default settings and
custom set points must be re-entered to unit
A remote wired controller is controlling
temperature set point. Release override
control of this remote (see “Remote Control
Panel Functions”) or change set point to
desired temperature with that remote.
Desired water flow is above maximum
capacity of unit. Reduce user flows to re-
establish control of temperature
If incoming water to unit is very warm and
the flow is just above minimum
requirements, the heat generated by the
burner while operating at minimum capacity
can make the water hotter than desired.
Increase the hot water user flow so that the
burner system can control the temperature.
Hot water flow
produced is lower than
expected
Water source is restricted
Heat exchanger in unit is
scaled
Incoming water temperature
is colder than expected
Check and fully open water inlet valve(s)
Check and clean inlet water screen
Clean heat exchanger by flushing per
maintenance procedure.
Colder than normal incoming supply water
will reduce the amount of hot water than can
be produced. Although the amount of heat
output from the unit is still at full capacity,
you must reduce the user flow and operate
within the capacity range of the heater.
The hot water coming
appears white and
turbid.
Small bubbles may appear
when water is heated. Air
dissolved in water may
evolve when water is
heated.
None. Normal operation.