A.O. Smith T-H2-DV Service Manual page 53

Error Code
1. Hi-limit switch trip /
Overheat cutoff fuse compromised
NOTE: When these components are compromised,
711
the "711" error code may appear instead of
the "111" or "121" error codes.
2. Driving circuit fault for gas solenoid valve (VG
1(A) Hi-limit switch trips
1(B) Overheat cutoff fuse compromised
2 PCB and/or gas valve fault (Refer to section 10-5 & 10-18)
Error Code
False flame detection
721
1 False flame detection (5 sec.)
Flame rod (Insulated resistance) fault
Error Code
741
Miscommunication between water heater and
temperature remote controller
1 Temperature remote controller (TM-RE30) or PCB fault
2 Check for signs of power surges.
Malfunction description
Visual insplection: connection/breakage of wires.
Normal: Less than 1 Ω between blue & blue
Visual inspection: connection/breakage of wires.
Normal: Less than 1 Ω between blue & blue
Visual inspection PCB: connection/breakage of wires and/or burn
makes on the computer board.
Malfunction description
Malfunction description
T-H2-DV/T-H2-OS Service Manual
Turn off the power supply
)
0
Diagnosis
(Refer to section 10-14)
(Refer to section 10-16)
Turn off the power or water supply
Diagnosis
Restoring
between the water heater and the
Remote controller (TM-RE30). When the
computer detects proper connections
between the water heater and the
remote controller, "741" error code will
cease to display.
Diagnosis
53
CONFIDENTIAL
Ver. 1.01
Cancellation method
Checkpoint
Cancellation method
Checkpoint
Cancellation method
proper cable connections
Checkpoint
C1
C2
C
I