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Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
Error Code
Malfunction description
Cancellation method
721
False flame detection
Turn off the power or water supply
Diagnosis
Check point
1 False flame detection (5 sec.)
2 Check for damp of flame rod.
I
Error Code
Malfunction description
Cancellation method
741
Miscommunication between water heater and
temperature remote controller
Restoring proper cable connections
between the water heater and
the Remote controller. When the
computer detects proper connections
between the water heater and the
remote controller, "741" error code
will cease to display.
Diagnosis
Check point
1 Temperature remote controller or PCB fault
Normal: 11 to 25 VDC between (white-black)
2 Check for signs of power surges.
F
Error Code
Malfunction description
Cancellation method
701
711
1 PCB fault
[1] Fault of preparation for the outlet thermistor
operation.
[2] Fault of driving circuit for Gas Proportional
Valve(VG
0
)
(701 error code)
Turn off the power or water supply
(711 error code)
Turn off the power supply
Diagnosis
Check point
1 Check the PCB and/or gas proportional valve
(Refer to section 10-4 & 10-18)
Visual inspection PCB: connection/breakage of wires and/or
burn marks on the computer board.
Visual inspection gas proportional valve: connection/breakage
of wires of the gas proportional valve.
Normal: 20 to 40 Ω between (white) & (red)
H1