A.O. Smith T-KJr2-OS User Manual

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 operatio
n)
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

A.O. Smith T-KJr2-OS Specifications

General

Brand	A.O. Smith
Model	T-KJr2-OS
Category	Water Heater
Language	English