110 Indoor / 110 Outdoor Service Manual
Ver. 1.01
41
CONFIDENTIAL
Error Code
Malfunction description
Cancellation method
51
Fault of driving circuit for main gas solenoid
valve (MV)
Turn off the power supply
(The computer checks the condition of the main
gas valve immediately after every operation)
Diagnosis
Checkpoint
1 PCB and/or main gas valve fault
(Refer to section 10-4 & 10-14)
Visual inspection of gas valves: connection/breakage of wires.
Normal: 78 to 100 VDC between COM (blue) & #3 (light blue)
(during operation)
Visual inspection of PCB: connection/breakage of wires and/or burn marks
on the computer board.
2 Main gas valve fault
C
Error Code
Malfunction description
Cancellation method
55
Fault of driving circuit for any of the gas
solenoid valves (SV
1
, SV
2
, and/or SV
3
)
Turn off the power supply
(The computer checks the condition of the
solenoid valves 6 hours after every operation)
Diagnosis
Checkpoint
1 PCB and/or gas valve fault (Refer to section 10-4 & 10-14)
Visual inspection of gas valves: connection/breakage of wires.
Normal: 78 to VDC between COM (blue) & #9 (green)
(during operation)
Normal: 78 to VDC between COM (blue) & #53 (orange)
(during operation)
Normal: 78 to VDC between COM (blue) & #73 (red)
(during operation)
Visual inspection of PCB: connection/breakage of wires and/or burn marks
on the computer board.
2 Gas solenoid valve fault (SV
1
, SV
2
, and/or SV
3
)
C
