Takagi JT-H2-DV Maintenance

M M a a i i n n t t e e n n a a n n c c e e s s h h e e e e t t
A.
Troubleshooting
If the error code is indicated on the 3‐digit 7‐Seg LED 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 fully open, the gas line sized properly and the gas supplies
pressure enough. Refer to the "Gas supply and gas pipe sizing" of the installation manual.
・ Check the set temperature, and change the dipswitch setting. Refer to Section D.
・ Refer to "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 cleaned. (Part #409)
・ Check if the gas line sized properly and the supply gas pressure sufficient.
・ Check for cross connection between cold water lines and hot water lines.
・ Refer to "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 the green LED will lit.
・ Check if the filter on the cold water inlet cleaned. (Part #409)
B.
*The 341, 621 and 941 error codes are applied to
Error codes
the 520H and 320H Direct Vent Indoor model only.
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 water heater. If it's wrong gas type model, replace the water heater to correct one.
・ Check if there is any blockage (For example, Damper sticking, Vent Flaps installed on the
terminator, Snow build up around terminator, Installed in a closet (No ventilation or lack
of combustion air)) in the intake air and/or exhaust. Refer to the "Vent termination
clearances" of the installation manual.
・ If the water heater is installed as a direct‐vent system, check whether there are enough
distance between the intake air terminal and the exhaust terminal. Refer to the "Vent
termination clearances" of the installation manual.
・ Check if the total vent length doesn't exceed 50 ft and the # of elbows is less than 5Ea.
・ Check the altitude/elevation of area of where the water heater installed. Refer to the
"High‐altitude function" of the 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
#114), especially if the water heater has been installed in a contaminated area.
・ Check if there is dust and lint in heat exchanger.
・ Check the manifold pressure of the water heater. Refer to installation manual.
111: Ignition failure
1. Check gas supply and inlet gas pressure.
2. Check if the Hi‐limit switch (Part #432) is properly functioning.
3. Check for connection/breakage of wires (Part #110, 404, 704, 705, 710, 719), burn marks
on the computer board (Part #701), and/or soot on the flame rod (Part #106). And then if
O.H.C.F (Part #008 and/or #404) is 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 valves assembly (Part #118)
when water heater goes into combustion.
6. (Only no sparking and/or kick sound) Check voltage on each wire to gas valves assembly
(Part #118) and/or the igniter (Part #123). Refer to the "Appendix A" in Section C.
*No sparking sound >>>>> Refer to the #1 at "Appendix A" in Section C.
*No kick sound >>>>> Refer to the #2 at "Appendix A" in Section C.
7. Check if there is leaking from heat exchanger (Part #401 or 456)
8. Check if there is dust and lint in nozzles of the manifold (Part #118).
9. Check current on the flame rod (Part #106). Refer to the #3 at "Appendix A" in Section C.
121: Loss of flame
1. Check gas supply and inlet gas pressure.
2. Check if the Hi‐limit switch (Part #432) is properly functioning.
3. Check for connection/breakage of wires (Part #110, 404, 704, 705, 710, 719), burn marks
on the computer board (Part #701), and/or soot on the flame rod (Part #106). And then
if O.H.C.F (Part #008 and/or #404) is breakage, Consult the manufacturer.
4. Check if there is leakage from heat exchanger (Part #401 or 456).
5. Check if there is dust and lint in nozzles of the manifold (Part #118).
6. Check current on the flame rod (Part #106). Refer to the #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 thermistor (Part #422, 433, 418, 706, 707,721).
・ Check thermistor resistance. Refer to the "Appendix D" in Section C.
391: Air‐fuel Ratio Rod failure
・ Check for connection/breakage of wires (Part #710) and/or soot on the AFR rod. (Part #106).
J J T T H H 2 2
7 7 3 3 W W 0 0 0 0 3 3
<<The fan motor still spinning after operation has stopped>>
・ This is normal. After operation has stopped, the fan motor keeps running for 35 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 "Error 101" in the
Section B.
<<Power supply circuit>>
1. If the remote controller installed, press the "ON/OFF" button of the remote controller,
and make sure that the green LED on the "ON/OFF" button of the remote controller is lit.
Restart the water heater.
2. Check if that the 3‐digit 7‐Seg 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 #715), 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 3‐digit 7‐Seg LED on the PCB (Part #701) isn't lit, some electrical parts can be
broken. Consult the manufacturer.
<<Water circuit>>
1. If you set the remote controller, turn the power button on and then the green LED will lit.
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 to operate.
3. Check for reverse connection and cross connection.
4. Check if the filter on the cold water inlet cleaned. (Part #409)
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
installation manual to protect your water heater from freeze.
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 #423, 429).
9. Check if the motor drive of the water control valve (Part #423) is locked due to scale
buildup, and/or water leakage, Consult the manufacturer.
441: Flow Sensor failure (Only Easy‐Link system)
・ Check for connection/breakage of wires and/or debris on impeller (Part #429, 708).
510,551: Abnormal Main and Gas Solenoid Valve
・ Check for connection/breakage of wires (Part #705) and/or burn marks on the computer board (Part #701).
・ Reset power supply of the water heater.
・ Check voltage on the each valve on the gas valves assembly (Part #118). Refer to the
"Appendix C" in Section C.
611,621*: Fan motor and Exhaust Fan motor fault
・ Check for connection/breakage of wires, dust buildup in the fan motor/Exhaust fan motor
(Part #114,124) and/or burn marks on the computer board (Part #701).
・ Check for frozen/corrosion of connectors of the fan motor (Part #114,124).
・ Check voltage between blue wire and each wire of the fan motor (Part #114,124) during
operation. Refer to the "Appendix B" in Section C.
631: Abnormal External Pump
・ Check whether the pump connected to PCB (Part #701) works properly.
651,661: Water control valve fault (Only Easy‐Link system)
・ Check the water control valve (Part #423), connection/breakage of wires (Part #423),
motor drive locked due to scale buildup, and/or water leakage.
・ Check voltage between black wire and red wire. Refer to the "Appendix F" in Section C.
701: Computer board fault
・ Check for connection/breakage of wires (Part #708) and/or burn marks on the computer board (Part #701).
711: Hi‐limit switch trip/ Gas solenoid valve drive circuit failure
・ Check connection/breakage of wires (Part #705) and/or burn marks on the computer
board (Part #701).
721: False flame detection
1. Clean the flame rod (Part #106).
2. For indoor models, check if condensate drain is installed on the vent collar of the water heater.
3. Check if there is leaking from heat exchanger (Part #401 or 456).
741: Miscommunication between water heater and remote controller
1. Check the model type of the remote controller. Model name 9007603005 (TM‐RE30) is the
correct one.
2. Inspect for the connections between the water heater and remote controller. Refer to
"Remote controller connections" section in the Installation manual.
3. Check the power supply of the water heater.
4. If this error code appears only the 3‐digit 7‐Seg LED on the PCB (Part #701), check the voltage
on the remote controller terminal on the PCB. Refer to the "Appendix E" in Section C.
5. If this error code appears only remote controller, replace the PCB (Part #701).
6. If this error code appears both the PCB (Part #701) and the remote controller, replace the
remote controller.
761: Miscommunication between Parent unit and Child units for Easy‐link
system (Only 520H models)
・ Check if connection between the parent unit and the child units are correct. Refer to
"Easy‐Link system" section in the Installation manual.
941*: Abnormal exhaust temperature (Only 520H and 320H Direct Vent Indoor)
・
Check if the set temperature is higher than 140°F (60°C) and the system is Recirculation.
・
Check exhaust thermistor resistance. Refer to the "Appendix D" in Section C.
991: Imperfect combustion
・ Refer to the "Error code 101" in this section.
C.
Wiring Diagram and check point of the Water heater
BK: BLACK R: RED
W: WHITE BL: BLUE
G: GREEN
O: ORANGE
Y: YELLOW BR:BROWN
M I N b u t t o n D e c r e a s e b u t t o n
M A X b u t t o n
7 S e g L E D
I n c r e a s e b u t t o n
N u m b e r d i s p l a y b u t t o n
E r r o r c a l l b u t t o n
Gas
F
Propor- H1
W W
tional R R
R i g h t b a n k
Valve
o f d i p s w i t c h e s
L e f t b a n k
Flow
H2
B K B K
o f d i p s w i t c h e s
Sensor W W
R R
E2
Output
B K
thermistor
B K
E3
Inlet B K
B K
B K
thermistor
520H / 320H Direct
E1
Mixing
B K Vent Indoor Only
thermistor
K1
Exhaust
W
thermistor
W
K2
Hi-limit switch
W W
for exhaust
R
C
O I
SV2 G
L B
B L
SV1
SV3
H i - l i m i t P u m p p o r t
s w i t c h
MV
C1
B L
520H / 320H Direct
B L
B L B L Vent Indoor Only
G1
A
B L B L
C2
O.H.C.F
B L
B L G2
O.H.C.F W W
O O
Y Y
A2
BL BL
R R
Fan
motor
A1
Fan motor for
exhaust
Appendix A (For error code 111)
Check these points during ignition stage.
# 1. Refer check point "B2" on the wiring diagram above.
Check voltage between purple wires.
(Normal: 90 to 110 VAC)
This Check point is normal?
Yes >> Replace the igniter (Part #123)
No >> Go to Next
# 2. Refer check point "C" and "H1" on the wiring diagram above.
Check the voltage bellows.
C: Between blue wire and light blue wire (#3).
(Normal: 78 to 100 VDC)
C: Between blue wire and orange wire (#53).
(Normal: 78 to 100 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 valves assembly. (Part #118)
No >> Replace the PCB. (Part #701)
# 3. Check current thought the orange flame rod wire (Part #710).
(Normal: more than 1μA)
This check point is normal during operation?
Yes >> Replace the PCB. (Part #701)
No >> Replace the flame rod. (Part #106)
D.
Dipswitch Settings on the computer board of the water heater
Change the dipswitch settings when the power supply is turning off.
The dark square is the direction the dipswitch should be set to.
DEFAULT is the factory setting.
<Left bank of dipswitches>
The Gas Type and Model Type dipswitch should
already be properly preset from the factory.
Model type
Gas type
520H Direct 520H Outdoor
Natural
Vent Indoor
and
Propane
and
Gas 320H Outdoor
320H Direct
Vent Indoor
Appendix B (For error code 611 and 621)
P: PURPLE
Refer check point "G1" & "G2" in the diagram to the left and followings.
LB:LIGHT BLUE
・ Check voltage between red wire and blue wire.
B u r n i n g l a m p (Normal: 110 to 160 VDC)
D2
・ Check voltage between yellow wire and blue wire.
W
Parent
W
(Normal: 13 to 17 VDC)
R
D1
1
R
・ Check voltage between orange wire and blue wire
B K B L
2
B K B L
(Normal: 2.0 to 6.5 VDC)
9007603005
All check points are normal?
(TM‐RE30)
Re mo te c on tr ol le r
Yes >> Replace the fan motor and Exhaust fan motor. (Part #114&124)
No >> Replace the PCB. (Part #701)
Water
Control
Appendix C (For error code: 510 and 551)
valve
R Refer check point "C" in the diagram to the left and followings.
Y G
W
Check voltage on the each valve on the gas valves assembly.
BK
BR
R ・ Between blue wire and light blue wire (#3). (Normal: 78 to 100 VDC)
O
Y
J
G
・ Between blue wire and green wire (#9). (Normal: 78 to 100 VDC)
W
BK
BL
・ Between blue wire and orange wire (#53). (Normal: 78 to 100 VDC)
O Flame rod
・ Between blue wire and red wire (#73). (Normal: 78 to 100 VDC)
G
Ground
All check points are normal?
Air-fuel
Y
ratio rod
Yes >> Replace the gas valves assembly. (Part #118)
A l a r m
Heaters
p o r t
No >> Replace the PCB. (Part #701)
B1
BK
BK Appendix D (For error code: 311, 321, 331, 341 and 941)
B2
・ Mixing thermistor (Find the marking of No.113 on the connector)
Check point "E1"
Freeze protection
・ Output thermistor (Find the marking of No.12 on the connector)
thermostat
Check point "E2"
I G
P P
・ Inlet thermistor (Find the marking of No.42 on the connector)
P
P
Check point "E3"
Igniter
Check resistance between black wire and black wire.
rod
°F 50 59 68
Temperature
°C 10 15 20
Resistance kΩ 15.4 12.6 10.3
・ Exhaust thermistor (Find the marking of No.52 on the connector)
Check point "K1"
Check resistance between white wire and white wire.
°F 50 59 68
Temperature
°C 10 15 20
Resistance kΩ 19.5 15.9 13.0
All check points are normal?
Yes >> Replace the PCB. (Part #701)
No >> Replace the wrong thermistor. (Part #422, 433, 418, 706)
Appendix E (For error code: 741)
Refer check point "F" on the wiring diagram above.
Check voltage on the remote controller terminal on the PCB. (Normal: 11 to 25 VDC)
This check point is normal?
Yes >> Replace the remote controller.
No >> Replace the PCB. (Part #701)
Appendix F (For error code: 651 and 661)
Refer check point "J" on the wiring diagram above.
Check voltage between blue wire and brown wire. (Normal: 13 to 16 VDC)
This check point is normal?
Yes >> Replace the Water control valve. (Part #423)
No >> Replace the PCB. (Part #701)
Left bank
<Right bank of dipswitches>
High‐altitude function Easy‐Link system
Parent
FM+ FM++
DEFAULT
Over
Unit
(2,500 to (4,000 to
(0 to
5,000 ft:
4,000 ft) 5,000 ft)
2,500 ft)
Consult
the
manufacturer
FM speed is increased automatically. Single unit is the same as the child unit.
77 86 95
25 30 35
8.5 7.0 5.9
77 86 95
25 30 35
10.7 8.9 7.4
Right bank
Child
Unit
DEFAULT