A.O. Smith T-M50 ASME Service Manual page 43

Error Code
Fault of driving circuit for any of the gas
solenoid valves (SV
551
(The computer checks the condition of the
solenoid valves 6 hours after every operation)
1 Left and/or Right PCB and/or gas valve fault
(Refer to section 10-4 & 10-14)
V isual inspection of gas valves: connection/breakage of wires.
Normal: 78 to 100 VDC between COM (blue) & #9 (green)
(during operation)
Normal: 78 to 100 VDC between COM (blue) & #53 (orange)
(during operation)
Normal: 78 to 100 VDC between COM (blue) & #73 (red)
(during operation)
V isual inspection of PCB: connection/breakage of wires and/or burn marks
on the computer board.
2 Gas solenoid valve fault (SV
Error Code
Fan motor fault
611
1 PCB and fan motor fault
V isual inspection of fan motor: connection/breakage of wires or dust
buildup (causing electrical shortage)
Normal: 110 to 160 VDC between red & blue (during operation)
Normal: 13 to 17 VDC between yellow & blue (during operation)
Normal: 2.0 to 6.5 VDC between orange & blue (during operation)
Verify fan motor speed of the water heater using the "diagnostics mode" of
the temperature remote controller. See the "12-1. How to diagnose the
water heater using the remote controller."
V isual inspection of Left and/or Right PCB: connection/breakage of wires
and/or burn marks on the computer board.
Malfunction description
, SV , and/or SV
1 2
, SV
1
Malfunction description
(Refer to section 10-3,10-14 & 10-15)
T-M50 / T-M50 ASME Service manual
)
3
Turn off the power supply
Diagnosis
, and/or SV )
2 3
Turn off the power or water supply
Diagnosis
43
CONFIDENTIAL
Ver. 1.05
Cancellation method
Checkpoint
Cancellation method
Checkpoint
C
G