Replacement Parts List
Maintenance sheet
68A166-1
B. Error codes
031: Incorrect DIPswitch setting
・
Check the DIPswitch settings on the PCB. Refer to Section D.
101: Warning for the “991” error code
・
Check the gas type of the house (and/or the building).
・
Check if there is any blockage in the intake air and/or exhaust. Refer to the “Venting
Instructions” of the Installation manual.
・
If the water heater is installed as a direct-vent system, check whether there is enough
distance between the intake air terminal and the exhaust terminal. Refer to the “Vent
termination clearances” of the Installation manual.
・
Check the total vent length. Refer to the "Venting instructions" of the Installation manual.
・
Check the altitude/elevation of area of where the water heater is installed. Refer to the
“High-altitude function” of Section D. And change the DIPswitch settings.
・
Check if there is grease and/or dirt in the burner (Part #101) and the fan motor
(Part #103), especially if the water heater has been installed in a contaminated area.
・
Check if there is dust and lint in the heat exchanger.
・
Check the manifold pressure of the water heater. Refer to the Installation manual of the water heater.
111: Ignition failure
1. Check the gas supply and inlet gas pressure.
2. Check if the Hi-limit switch (Part #412) is properly functioning.
3. Check for connection/breakage of wires (Part #413, 708, 709, 710, 712), and/or soot on the
flame rod (Part #108). And then if the O.H.C.F (Part #413) has a breakage, Consult the
manufacturer.
4. Check if there is a buzzing spark ignition sound coming from the burner (Part #101)
when water heater prepares for combustion.
5. Listen for the double “clunk” sound coming from the gas valve assembly (Part #102)
when water heater goes into combustion.
6. (Only if sparking and/or kick sound) Check the voltage on each wire to gas valve assembly
(Part #102) and/or the igniter assembly (Part #711). Refer to “Appendix A” in Section C.
*No sparking sound >>>>> Refer to #1 at “Appendix A” in Section C.
*No kick sound >>>>> Refer to #2 at “Appendix A” in Section C.
7. Check if there is leaking from the heat exchanger (Part #401).
8. Check if there is dust and lint in nozzles of the manifold (Part #102).
9. Check the current on the flame rod (Part #108). Refer to #3 at “Appendix A” in Section C.
121: Loss of flame
1. Check the gas supply and inlet gas pressure.
2. Check if the Hi-limit switch (Part #412) is properly functioning.
3. Check for connection/breakage of wires (Part #413, 708, 709, 712), burn marks on the
computer board (Part #701), and/or soot on the flame rod (Part #108). And then if the
O.H.C.F (Part #413) has a breakage, Consult the manufacturer.
4. Check if there is leaking from the heat exchanger (Part #401).
5. Check if there is dust and lint in nozzles of the manifold (Part #102).
6. Check the current on the flame rod (Part #108). Refer to #3 at “Appendix A” in Section C.
311,321,331,341*: Disconnected/short-circuited thermistor
・
Check for connection/breakage of wires and/or debris on the thermistor (Part #407, 408, 411, 715, 718).
・
Check the thermistor resistance. Refer to “Appendix D” in Section C.
391: Air-fuel ratio rod failure
・
Check for connection/breakage of wires (Part #709) and/or soot on the flame rod (Part #108).
441: Flow sensor failure (Only Easy-Link system)
・
Check for connection/breakage of wires and/or debris on the flow sensor impeller (Part #402).
510,551: Abnormal main gas solenoid valve and gas solenoid valve
・
Check for connection/breakage of wires (Part #708) and/or burn marks on the computer board (Part #701).
・
Reset power supply of the water heater.
・
Check the voltage of each valve on the gas valve assembly (Part #102). Refer to “Appendix C” in Section C.
611: Fan motor fault
・
Check for connection/breakage of wires, dust buildup in the fan motor (Part #103) and/or
burn marks on the computer board (Part #701).
・
Check for frozen/corrosion of connectors of the fan motor (Part #103).
・
Check the voltage between blue wire and each wire of the fan motor (Part #103). Refer to
“Appendix B” in Section C.
651: Flow adjustment valve fault (Only Easy-Link system)
・
Inspect the flow adjustment valve (Part #402), for connection/breakage of wires, locked
motor drive due to scale buildup, and/or water leakage.
・
Check the voltage between black wire and red wire. Refer to “Appendix F” in Section C.
661: Bypass valve fault
・
Inspect the bypass valve (Part #403), for connection/breakage of wires, locked motor drive
due to scale buildup, and/or water leakage.
・
Check the voltage between brown wire and red wire. Refer to “Appendix F” in Section C.
701: Computer board fault
・
Check for connection/breakage of wires (Part #714), and check the resistance between
white wire and red wire. Refer to “Appendix A” in Section C.
711: Gas solenoid valve drive circuit failure
・
Refer to the “111” and “121” error codes in this section.
721: False flame detection
1. Clean the flame rod (Part #108).
2. Check if there is leaking from the heat exchanger (Part #401).
741: Miscommunication between water heater and remote controller
1. Check the model type of the remote controller. Model No. 9008172005 (TM-RE40) is the correct one.
2. Inspect the connections between the water heater and remote controller. Refer to the
“Remote controller connections” of the Installation manual.
3. Check the power supply of the water heater.
4. If this error code appears only on the green LED in the PCB (Part #701), check the voltage on
the remote controller terminal on the PCB. Refer to “Appendix E” in Section C.
5. If this error code appears only on the remote controller, replace the PCB (Part #701).
6. If this error code appears on both the PCB (Part #701) and the remote controller, replace the remote controller.
751*: Miscommunication between water heater and temperature controller
1. Check the power supply of the water heater.
2. If this error code appears only on the green LED in the PCB (Part #701), check the voltage on
the remote controller terminal on the PCB. Refer to “Appendix E” in Section C.
3. If this error code appears only on the temperature controller, replace the PCB (Part #701).
4. If this error code appears on both the PCB (Part #701) and the temperature controller,
replace the temperature controller.
761: Miscommunication between Parent unit and Child units for Easy-link system
・
Check if the connections between the parent unit and the child units are correct. Refer to
the “Easy-Link system” section in the Installation manual.
941*: Abnormal exhaust temperature (Only 540 (T-H3) Indoor models)
・
Check for connection/breakage of wires, dust buildup in the fan motor (Part #103) and/or
burn marks on the computer board (Part #701).
・
Check the exhaust thermistor resistance. Refer to "Appendix D" in Section C.
991: Imperfect combustion
・
Refer to the “101” error code in this section.
C. Wiring diagram and check point of the water heater
Appendix A (For error code 111)
Check the following points during ignition stage.
# 1. Refer to check point “B” on the wiring diagram above.
Check the voltage between purple wires. (Normal: 108 to 132 VAC)
This check point is normal?
Yes >> Replace the igniter assembly (Part #711).
No >> Go to Next.
# 2. Refer to check points “C” and “H1” on the wiring diagram above.
Check the voltages below:
C: Between blue wire and light blue wire (#3). (Normal: 93 to 120 VDC)
C: Between blue wire and orange wire (#53).
(Normal: 93 to 120 VDC)
H1: Check the voltage between white wire and red wire.
(Normal: 1 to 15 VDC)
These check points are normal?
Yes >> Replace the gas valve assembly (Part #102).
No >> Replace the PCB (Part #701).
# 3. Check the current through the yellow flame rod wire (Part #709).
(Normal: more than 5 μA)
This check point is normal during operation?
Yes >> Replace the PCB (Part #701).
No >> Replace the flame rod (Part #108).
Appendix B (For error code 611)
Refer to check point “G” in the diagram to the left and the following.
•
Check the voltage between red wire and blue wire (Normal: 132 to 192 VDC).
•
Check the voltage between yellow wire and blue wire (Normal: 13 to 17 VDC).
•
Check the voltage between orange wire and blue wire (Normal: 2.0 to 6.5 VDC).
All check points are normal?
Yes >> Replace the fan motor (Part #103).
No >> Replace the PCB (Part #701).
Appendix C (For error code 510 and 551)
Refer to check point “C” in the diagram to the left and the following.
Check the voltage on each valve on the gas valve assembly.
•
Between blue wire and light blue wire (#3) (Normal: 93 to 120 VDC).
•
Between blue wire and green wire (#9) (Normal: 93 to 120 VDC).
•
Between blue wire and orange wire (#53) (Normal: 93 to 120 VDC).
•
Between blue wire and red wire (#73) (Normal: 93 to 120 VDC).
All check points are normal?
Yes >> Replace the gas valve assembly (Part #102).
No >> Replace the PCB (Part #701).
Appendix D (For error code 311, 321, 331, 341, and 941)
•
Outlet thermistor (Find the marking of No.113 on the connector)
Check point “E1”
•
Inlet thermistor (Find the marking of No.42 on the connector)
Check point “E2”
•
Heat exchanger thermistor (Find the marking of No.12 on the connector)
Check point “E3”
Check the resistance between black wire and black wire.
•
Exhaust thermistor
Check point “K1”
Check the resistance between white wire and white wire.
All check points are normal?
Yes >> Replace the PCB (Part #701).
No >> Replace the thermistor (Part #407, 408, 411, 718).
Appendix E (For error code 741 and 751)
Error code 741: Refer to check point “F” on the wiring diagram above.
Error code 751 : Refer to check point “L” on the wiring diagram above.
Check the voltage on the remote controller and/or temperature controller
on the PCB.
•
Between black wire and white wire. (Normal: 11 to 25 VDC)
This check point is normal?
Yes >> Replace the remote controller and/or temperature controller.
No >> Replace the PCB (Part #701).
If the error code is indicated on the green LED (Refer to Section C) on the PCB (Part #701) of
the water heater (and/or the remote controller), refer to Section B.
<< It takes long time to get hot water at the fixtures >>
・
The time it takes to deliver hot water from the water heater to your fixtures depends
on the length of piping between the two. The longer the distance or the bigger the
pipes, the longer it will take to get hot water.
・
If you would like to receive hot water to your fixtures quicker, you may want to
consider a hot water recirculation system.
<< The water is not hot enough or turns cold and stays cold >>
・
Compare the flow and temperature. Refer to the “Output temperature chart” of the
Installation manual.
・
Check cross plumbing between cold water lines and hot water lines.
・
Check if the gas supply valve is fully open, the gas line is sized properly and the gas
supplies enough pressure. Refer to the “Gas supply and gas pipe sizing” of the
Installation manual.
・
Check the set temperature, and change the set temperature with the remote controller
or the DIPswitch setting. Refer to Section D.
・
Refer to the “Water circuit” in this section.
<<The water is too hot>>
・
Check the set temperature, lower setting temperature.
<<The hot water is not available when a fixture is opened>>
・
Refer to the “Power supply circuit” and “Water circuit” in this section.
<<Fluctuation in hot water temperature>>
・
Check if the filter on the cold water inlet is cleaned. (Part #406)
・
Check if the gas line is sized properly and the supply gas pressure is sufficient.
・
Check for cross connection between cold water lines and hot water lines.
・
Refer to the “Water circuit” in this section.
<<Unit does not ignite when water goes through the water heater>>
・
Refer to the “Power supply circuit” and “Water circuit” in this section.
・
If you use the remote controller, turn the power button on and then check if the
STAND BY LED will light up.
・
Check if the filter on the cold water inlet is cleaned (Part #406).
・
Refer to the “Water circuit” in this section.
A. Troubleshooting
<<The fan motor is still spinning after operation has stopped>>
・
This is normal. After operation has stopped, the fan motor keeps running from 15 to 70
seconds in order to re-ignite quickly, as well as purge all the exhaust gas out of the flue.
<<Abnormal sound from water heater>>
・
An abnormal sound from the water heaters is caused by not enough air supply or wrong
installations. The water heater needs more combustion air. Refer to the “101” error code
in the section B.
<<Power supply circuit>>
1. If the remote controller is installed, press the “ON/OFF” button of the remote controller, and
make sure that the STAND BY LED next to the “ON/OFF” button of the remote controller is lit.
Restart the water heater.
2. Check if the green LED on the PCB (Part #701) of the water heater is lit. If so, the power
supply circuit of the water heater is under normal condition. Next, refer to the
“Water circuit” in this section.
3. Check the fuse on the surge box (Part #703), and if it has a brown spot, need to replace it.
4. Check the power supply, and make sure that the water heater has 120 VAC.
5. If the green LED on the PCB (Part #701) isn’t lit, some electrical parts can be broken. Consult
the manufacturer.
<<Water circuit>>
1. If you use the remote controller, turn the power button on and then check if the
STAND BY LED will light up.
2. Open all hot water faucets, and make sure that there is enough water flow. This
water heater needs at least 0.5 GPM water flow (at the default set temperature) to operate.
3. Check for reverse connection and cross connection.
4. Check if the filter on the cold water inlet is cleaned (Part #406).
5. Check if there is no debris or obstruction on the fixtures.
6. Check if water ways in the water heater are frozen. If so, unfreeze them. And refer to the
Installation manual to protect your water heater from freezing.
7. Check if the inlet water pressure is higher than 40 psi. And if it’s lower than 40 psi, need
to increase the pressure.
8. Check for connections and breakage of wires (Part #402).
9. Check if the motor drive of the flow adjustment valve (Part #402) is locked due to scale
buildup, and/or water leakage. If so, Consult the manufacturer.
Temperature
°F 50 59 68 77 86 95
°C 10 15 20 25 30 35
Resistance kΩ 15.4 12.6 10.3 8.5 7.0 5.9
ATH3
W: WHITE
R: RED
BK: BLACK
P: PURPLE
LB: LIGHT BLUE
BL: BLUE
G: GREEN
Y: YELLOW
O: ORANGE
BR: BROWN
Temperature
°F 50 59 68 77 86 95
°C 10 15 20 25 30 35
Resistance kΩ 19.5 15.9 13.0 10.7 8.9 7.4
D. DIPswitch settings on the computer board of the water heater
<Lower bank of
DIPswitches>
Temperature set
120 °F (49 °C)
DEFAULT
140 °F (60 °C)
OFF
ON
1 2 3 4 5 6
OFF
ON
1 2 3 4 5 62 3 4 5 6
Easy-Link system
Parent Unit
Child Unit
(DEFAULT)
OFF
ON
1 2 3 4 5 6
OFF
ON
1 2 3 4 5 6
Single unit is the same as the child unit.
Lower bank
Upper bank
Appendix F (For error code 651 and 661)
Error code 651 : Refer to check point “J” on the wiring diagram above. Check the voltage between black wire and red wire. (Normal: 7 to 16 VDC)
Error code 661 : Refer to check point “J1” on the wiring diagram above. Check the voltage between brown wire and red wire. (Normal: 3 to 11 VDC)
This check point is normal?
Yes >> Error code 651: Replace the Flow adjustment valve (Part #402). / Error code 661: Replace the Bypass valve (Part #403).
No >> Replace the PCB (Part #701).
High-altitude function
Indoor models
Outdoor models
DEFAULT DEFAULT
Up to 2,500 ft Up to 2,000 ft
Up to 5,000 ft Up to 4,000 ft
Up to 7,500 ft Up to 6,000 ft
Up to 10,100 ft Over 6,000 ft
Consult the
manufacturer
FM speed is increased automatically.
OFF
ON
1 2 3 4 5 6
OFF
ON
1 2 3 4 5 6
OFF
ON
1 2 3 4 5 6
OFF
ON
1 2 3 4 5 6
OFF
ON
1 2 3 4 5 6
OFF
ON
1 2 3 4 5 6
OFF
ON
1 2 3 4 5 6
OFF
ON
1 2 3 4 5 6
OFF
ON
1 2 3 4 5 6
*The 341, 751 and 941 error codes are applied to the 540 (T-H3)
Indoor models only.
<Upper bank of DIPswitches>
Locate the bank of DIPswitches at the bottom left of the computer board of the unit.
Change the DIPswitch settings when the power supply is turned off.
The dark square is the direction the DIPswitch should be set to. DEFAULT is the factory setting.
C
87
65
4
3
2
1
ON
654
3
2
1
ON
R
W
G
Y
PCB
W
120 VAC
G
Ground
SW
Ground
BK
W
G
BK
W
Surge
box
73
53
9
3
BL
BL
R
BK
R
W
BK
BK
BK
BK
BK
BK
W
BK
W
BK
Hi-limit switch
for exhaust
Exhaust
thermistor
W
W
W
W
Heater
Y
Y
Thermostat
BK
O
Ground
Flame rod
AFR rod
BK
W
Indoor
Only
540
W
BL
R
BK
Temperature controller
BK
BK
W
MAX buon
MIN buon
Increase buon
Decrease buon
Green LED
DIPswitches
Bypass
Valve
R
W
BR
Y
BL
Gas
Propor-
onal
Valve
R
Y
O
BL
W
FM
IG
Igniter rod
P
P
exchanger Heat
thermistor
Inlet thermistor
Outlet thermistor
Remote controller
Parent
1
2
Flow
Sensor
Flow
Adjust-
ment
Valve
Heater
Heater
540 Outdoor Only
Heater
Y
Y
Heater
Y
Y
Heater
Heater
540 Indoor Only
Hi-
switch
limit
O.H.C.F
MV
SV1
SV2
SV3
BL
BL
BL
BL
LB
G
O
R
BL
Only
Indoor
540
A1
A2
B1
G
A
B
C2
C1
H2
I
F
J
E1
E2
E3
H1
K1
K2
J1
D1
D2
L
Set DIPswitches shown in the table above depending on the vent length.
Vent settings (Indoor models only)
3" venting
5 to 20 ft (DEFAULT) 21 to 40 ft 41 to 70 ft
4" venting
5 to 50 ft (DEFAULT) 51 to 100 ft N/A
OFF
ON
1 2 3 4 5 6 7 8
OFF
ON
1 2 3 4 5 6 7 8
OFF
ON
1 2 3 4 5 6 7 8
*Factory setting
Gas type*
Propane
Natural
Gas
OFF
ON
1 2 3 4 5
OFF
ON
1 2 3 4 5
Model type*
Indoor model
Outdoor model
OFF
ON
1 2 3 4 5 6
OFF
ON
1 2 3 4 5 6