American Water Heater NonCondensing UltraLow NOx Outdoor Natural Gas GT110UNE user manual

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•	Priority Control Devices such as a flow switch, an Aquastat or other 
electronic controller can be used to prioritize the domestic water system over 
the heating system.
•	Follow all local codes, or in the absence of local codes, follow the most recent 
edition	of	the	 National	 Standard	 Code,	ANSI	Z21.10.3.
•	This illustration is a concept design only.  The reference to the 1/8th hole 
in check is only for the State of Massachusetts.  There are a wide variety 
of variations to the application of controls and equipment presented.  
Designers must add all necessary safety and auxiliary equipment to conform 
to code requirements and design practice.  For more details, contact the 
manufacturer.
NOTICE
120 VAC switch or outlet
Hot water outlet
Unions
T-handle	gas	shutoff	valve
Check valve
Electronically controlled pump	timer.		Activates	every 6 hours for 60 seconds.  Wire to product approved pump
Heating Coil(used with air-handler)
Cold water supply
3-inch gas exhaust vent (Discharge must comply with local and state codes.)  Cannot be common vented with other appliances
An approved temperature and pressure relief	valve.	Tie	to	location	approved	by	local	codes	and	must	meet	BTU	rating	of	water heater model used
Check valve will have 1/8-inch hole drilling in	clapper	optional
Atmosphericvacuum breaker
Shutoff 	  valve
Pressure gauge
Apply correct thermal expansion tank-size per	application
Shutoff	valves
Shutoff	valves
Check valves
Cold water inletGas inletWater filterDrain plugThermostatic	mixing	valveHot water supply and return to heating	coil
System installed with reverse acting	aquastat	to	shut	off	fan.	Suggested but not required by 248 CMR
50’-0” maximum distance from water heater to fan coil.(Developed length) Not including coil	in	heating	unit
NSF-61 product approved pump
Automatic	tempering	device	must be installed below the top of the water heater as per manufacturer’s recommendations
Piping loop between water heater and fan coil shall be in compliance with 248 CMR
Tempered water to plumbing	fixtures.		Must	meet temperature requirements of 248 CMR
All water piping should be insulated in accordance with 780 CMR (Massachusetts	energy	code)
-Dual-purpose hot water heating-
(Domestic and Space Heating):
Diagrammatic layout of radiant heating and domestic water heater per Mass. code.
     The recirculation pump is to provide no less than 2 GPM (7.5 L/min) and no more than 4 GPM (15 L/min)  
         through each activated unit in the system
Installation
Installation Manual
BallValveIsolationValve  
						

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INITIAL OPERATION
IF YOU SMELL GAS:
•	Do not try to start the water heater.
•	Do not touch any electric switches; do not use any phone in your building.
•	Immediately call your gas supplier from a neighbor’s phone.  Follow the gas 
supplier’s instructions.
•	If you cannot reach your gas supplier, call the fire department.WARNING
Operation
1.Once the above checks have been completed, please clean 
filter of any debris.  Refer to p. 41 for instructions.
2.Fully open the manual water control valve on the water 
supply line.
3.Open a hot water tap to verify that water is flowing to that 
tap.  Then close the hot water tap.
4.Fully open the manual gas control valve installed.
5.Turn on the 120 VAC, 60 Hz power supply to the water 
heater.
6.Now you are ready to enjoy hours of endless hot water.
•	Check the GAS and WATER CONNECTIONS for leaks before firing unit for the first time.
•	Open the main gas supply valve to the unit using only your hand to avoid any spark.  Never 
use tools.  If the knob will not turn by hand, do not try to force it; call a qualified service 
technician.  Forced repair may result in a fire or explosion due to gas leaks.
•	Be sure to check for the presence of leaking gas toward the bottom of the unit because 
some gases are heavier than air and may settle towards the floor.
•	Check the GAS PRESSURE.  Refer to p. 20.
•	Do not try to light the burner manually.  It is equipped with an electronic ignition device 
which automatically lights the burner.
•	Check for PROPER VENTING and COMBUSTIBLE AIR to the water heater.
•	Purge the GAS and WATER LINES to remove any air pockets.
•	Do not use this water heater if any part has been submersed under water.  Immediately call 
a qualified service technician to inspect the water heater and to replace any damaged parts.
FOR YOUR SAFETY, READ BEFORE OPERATING
Initial operation
Installation Manual  
						

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Owner's Guide
CONGRATULATIONS
Congratulations and thank you for choosing our tankless water heater. 
Before use, we recommend that you read through this safety manual 
carefully.  Please refer to the back of the manual for details about the 
warranty.  Keep this manual for future reference.
If you lose the manual, contact the manufacturer or your local 
distributor.  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.
Owner's Guide  
						

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OPERATING SAFETY
FOR YOUR SAFETY READ BEFORE OPERATING
A. This water heater does not have a pilot.  It is equipped with an ignition device that automatically 
lights the burner.  Do not try to light the burner by hand.
B. BEFORE OPERATING smell all around the water heater area for evidence of leaking gas.  Be sure to 
smell next to the floor because some gas is heavier than air and will settle on the floor.
 WHAT TO DO IF YOU SMELL GAS.
•	Do not try to light any appliance.
•	Do not touch any electric switch; do not use any phone in your building.
•	Immediately call your gas supplier from a neighbor's phone.  Follow the gas supplier's 
instructions.
•	If you cannot reach your gas supplier, call the fire department.
C. Use only your hand to turn the gas valve knob.  Never use tools.  If the knob will not turn by hand, 
don't try to repair it.  Call a qualified service technician.  Forced or attempted repair may result in 
a fire or explosion.
D. Do not use this water heater if any part has been under water.  Immediately call a qualified service 
technician to inspect the water heater and to replace any damaged parts.
OPERATING INSTRUCTIONS
1. STOP! Read the safety information above or in the Owner's Manual.
2. Turn off all electric power to the water heater.
3. Do not attempt to light the burner by hand.
4. Turn the manual gas valve located on the outside of the unit clockwise to the OFF position.
5. Wait five (5) minutes to clear out any gas.  If you then smell gas, STOP! Follow "B" in the safety 
      information above on this label.  If you don't smell gas, go to next step.
6. Turn the manual gas valve located on the outside of the unit counterclockwise to the ON position.
7. Turn on all electrical power to the water heater.
8. If the water heater will not operate, follow the instructions “to Turn Off Gas to Appliance" and 
     call your service technician or gas supplier.
TO TURN OFF GAS TO APPLIANCE
1. Turn off all electric power to the water heater if service is to be performed.
2. Turn the manual gas valve located on the outside of the unit clockwise to the OFF position.
    WARNING: If you do not follow these instructions exactly, a fire or explosion may result causing
    property damage, personal injury or loss of life.
Operating Safety
Owner's Guide  
						

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DANGER
Vapors from flammable liquids will explode and catch fire causing death or severe burns.
      Do not use or store flammable products such as gasoline, solvents or adhesives in the same room 
      or area near the water heater.
WARNING
The outlet hot water temperature of the water heater is factory set at 120 °F (50 °C).
Use this heater at your own risk.  The set outlet water temperature can cause severe burns instantly or 
death from scalding.  Test the water before bathing or showering.
Do not leave children or an infirm person in the bath unsupervised.
DANGER
WARNING: California Proposition 65 lists chemical substances known to the state to cause cancer, birth 
defects, death, serious illness or other reproductive harm.  This product may contain such substances, be 
their origin from fuel combustion (gas, oil) or components of the product itself.
Vapors:
      1. Cannot be seen
      2. Vapors are heavier than air
      3. Go a long way on the floor
      4. Can be carried from other rooms 
            to the main burner by air currents
Keep flammable products:
      1. Far away from heater
      2. In approved containers
      3. Tightly closed
      4. Out of children's reach
Hot Water Heater temperature over 125 °F (52 °C) can cause severe burns 
instantly or death from scalding.  Children, disabled and the elderly are at 
the highest risk of being scalded.  Feel water temperature before bathing or 
showering.  Temperature limiting valves are available.  Ask a professional.
WARNING: Do not install water heater where flammable products will be stored.
Read and follow water heater warnings and instructions.  If owner’s manual is missing, 
contact the manufacturer.
Operating Safety
Owner's Guide  
						

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NORMAL OPERATION
GENERAL
REMOTE CONTROLLER
The	illustration	below	shows	an	example	of	the	display.		The	exact	display	may	differ	from	examples.
"HOT" Button
"COLD" Button
"ON/OFF" Button
Press the "HOT" button or the 
"COLD" button to set the hot 
water temperature.
When the STAND BY LED is ON, the 
hot water temperature will be 
displayed.
Display for Temperature
Press this button to 
start or stop operation.
"INFO" Button
STAND BY LED (Orange)
IN USE LED (Green)
The indicator is ON to show that 
power is ON.
The indicator lights during combustion.
Each time the button is pressed,
the operation mode is selected
in the sequence of the following.
Inlet watertemperatureOutlet watertemperatureWater flow
Temperature above 125 °F (52 °C) can cause severe burns or death from scalding. 
Children, disabled and the elderly are at high risk of being injured.
CAUTION
The remote controller has an energy saving mode.  Five minutes after the\
 water 
heater stops operating, the backlight of the remote controller turns off. 
The backlight of the remote will turn back on once the water heater begins firing 
again.
1. Open a hot water tap.2. Mix cold water with the hot to get
    the correct temperature water.
3. Close the hot water tap.
•	Flow rate to activate the water heater: 0.5 gallon per minute at the default set
                                                                     temperature (1.9 L/min).
•	Flow rate to keep the water heater running: 0.4 gallon per minute (1.5 L/min).
NOTICE
Normal Operation
Owner's Guide  
						

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TEMPERATURE SETTINGS
-Set temperature-
TEMPERATURE TABLE OF REMOTE CONTROLLER
Normal Operation
Owner's Guide
°F100105110115120*125130135140
°C3840434550*52555760
a) For 110U (T-KJr2U) and 310U (T-K4U) models
°F100105110115120*125130135140145150155160 
°C3840434550*5255576063656870
b) For 510U (T-D2U) model
 *Factory setting (Default): 120 °F
OperationScreen
1.Turn on the 120 VAC power supply to the unit (the water heater or 
the multi-unit controller).
2.Press the "ON/OFF" button on the controller in order to turn the controller 
on.
3.When ON, the STAND BY LED is lit.
4.It shows the set temperature on its display as shown in the picture on the 
right. (EX.: 120 °F)
5.
Press the "HOT" button or the "COLD" button to set the temperature setting 
of the unit.
Increasing temperature from 120 °F (50 °C) to 125 °F (52 °C):
1. The water heater must be in Stand By to increase the temperature.
2. Press the "HOT" button to set 120 °F (50 °C).
3. Press and hold the "INFO" button and the "HOT" button for at least 3
    seconds.  The remote will emit a beep and change to 125 °F (52 °C).
4. Press the "HOT" button to set up to 140 °F (60 °C).
Increasing temperature above 140 °F (60 °C)
     -510U (T-D2U) model only-: 
1. The water heater must be in Stand By to increase the temperature.
2. Press the "HOT" button to set 140 °F (60 °C).
3. Press and hold the "INFO" button and the "HOT" button for at least 3 
seconds.  The remote will emit a beep and change to 145 °F (63 °C).
4. Press the "HOT" button to set up to 160 °F (70 °C).
(EX.: 120 °F)  
						

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ADDITIONAL FEATURES
-Information mode-
You can get some information about the water heater condition by pressing the "INFO" button.  For more 
information, follow the procedures below:
The remote controller has a function that can change units of temperature and flow rate from °F to °C and 
from gallon per minute to liter per minute and vice versa, please follow the procedures below:
Outlet water temperature
OperationScreen
1.Press the "ON/OFF" button on the remote in order to 
turn the remote controller on.
2.When ON, the STAND BY LED is lit.
3.The previous set temperature will be displayed on the 
screen.
4.Press the "INFO" buttons for at least 3 seconds.
5.The set temperature should now be displayed in the 
alternate unit of measurement.
(EX.: 100 °F)
-Unit conversion mode-
OperationScreen
1.First of all, inlet water temperature will be displayed on 
the remote controller by pressing the "INFO" button.
2.Outlet water temperature will be displayed on the 
remote controller by pressing the "INFO" button.
3.And then, water flow will be displayed on the remote 
controller by pressing the "INFO" button.
4.Press the "INFO" button to finish information mode.
Inlet water temperature
Water flow
Normal Operation
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TEMPERATURE SETTINGS ON THE PCB
(WITHOUT REMOTE CONTROLLER)
There are 2 preset temperatures (120 °F (50 °C) and 140 °F (60 °C)) that you can select from by changing 
the DIPswitch settings on the computer board without the remote controller.  See the table below.
When the remote controller is in normal operation, the set temperature of the remote controller is given 
priority over the set temperature of the DIPswitch settings.
NOTE:  Only change the switches with dark squares.  The dark squares
             indicate the direction the DIPswitches should be set to.
WARNING
•	DO NOT adjust the upper bank of DIPswitches for the 510U (T-D2U) model.
•	Turn off the power supply to the water heater before changing the DIPswitch 
settings.
•	The temperature has been preset at the factory to 120 °F (50 °C).
DIPswitches
Computer board
120 °F (50 °C) 
DEFAULT140 °F (60 °C) 
No. 9 : OFFNo. 9 : ON
110U (T-KJr2U) and 310U (T-K4U) models
OFF
ON123 4567 8910
OFF
ON1 23 4567 8910
Lower bank of 
DIPswitches
Computer board
Upper bank of 
DIPswitches
(Lower bank of DIPswitches)
120 °F (50 °C)
DEFAULT140 °F (60 °C)
No. 5 : OFFNo. 5 : ON
510U (T-D2U) model
OFF
ON1 23 45 6
OFF
ON123 4562 3 456
Normal Operation
Owner's Guide  
						

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FLOW
•	This unit comes equipped with heating blocks to protect it against damages associated with freezing.
•	For this freeze protection system to operate, there has to be electrical power to the unit.  Damage 
to the heat exchanger caused by freezing temperatures due to power loss is not covered under the 
warranty.  In cases where power losses can occur, consider the use of a backup power supply.
•	The freeze protection system will activate when the freeze protection thermostat senses air temperature below 
36.5 °F (2.5 °C).  
•	For the 110U Indoor (T-KJr2U-IN), 310U Indoor (T-K4U-IN) and 510U Indoor (T-D2U-IN) models:
•	In any areas subject to freezing temperatures, the manufacturer highly recommends an indoor 
installation with an indoor model.  In such an installation, freezing issues can only occur if cold 
air enters through the venting into the heat exchanger, whether by negative pressures within 
the installation location or by strong outside winds.
•	The manufacturer also highly recommends the use of a backflow preventer (sold separately)
       to minimize the amount of cold air entering through the exhaust venting when the water
       heater is off.
•	It is the installer’s responsibility to be aware of freezing issues and take all preventative measures.  The 
manufacturer will not be responsible for any damage to the heat exchanger as a result of freezing.
•	If you will not be using your heater for a long period of time:
  1.   Completely drain the water out of the unit.  Refer to p. 41.
  2.   Disconnect power to your heater.
 This will keep your unit from freezing and being damaged.
Appliance/UseFlow rate
GPM (US)L/min
Lavatory Faucet1.03.8
Bath Tub4.0 – 10.015.2 - 37.8
Shower2.07.5
Kitchen Sink1.55.6
Dishwasher1.55.6
Washing machine4.015.2
Household Flow Rates
Taken from UPC 2006
•	The flow rate through the water heater is limited 
to a maximum of 6.6 GPM (25 L/min) for the 110U 
(T-KJr2U) model, 8.0 GPM (30 L/min) for the 310U 
(T-K4U) model, and 10.0 GPM (38 L/min) for the 
510U (T-D2U) model.
•	The temperature setting, along with the supply 
temperature of the water will determine the flow 
rate output of the unit.
•	Please refer to the temperature vs. gallons per 
minute charts on p. 54 to determine the likely flow 
rates based on your local ground water temperature 
and your desired outlet water temperature.
•	Based on the United States Department of Energy 
     method of testing water heater output, the water
     heater is rated for gallons per hour (GPH) (liters per
     hour (L/hr)) or gallons per minute (GPM) (liters per
     minute (L/min)) for Natural Gas, when raising the 
     water temperature by 77 °F (43 C°) (from 58 °F to 
     135 °F (14 °C to 57 °C)). 
     See the chart on the right.
•	Refer to the table to the top right for typical 
household plumbing fixture flow rates to determine 
what the water heater can do in a household 
application.
Only pipes within the water heater are protected by the freeze protection system. 
Any water pipes (hot or cold) located outside the unit will not be protected. 
Properly protect and insulate these pipes from freezing.CAUTION
FREEZE PROTECTION SYSTEM
Unit: GPM (L/min)
ModelFlow rate
110U (T-KJr2U) Indoor3.0 (11.4)Outdoor
310U (T-K4U)Indoor4.1 (15.5)Outdoor
510U (T-D2U)Indoor4.2 (15.9)
Outdoor4.3 (16.3)
Normal Operation
Owner's Guide