A.O. Smith T-H2-DV Service Manual page 51

Error Code
Verify fan motor speed
"diagnostics mode" of the T-H2-DV/T-H2-OS computer board or the
621
TM-RE30 temperature remote controller.
See the "12-1. How to diagnose the water heater using the TM-RE30".
V isual inspection of PCB: connection/breakage of wires and/or burn marks
on the computer board.
Error Code
Abnormal External pump
631
1 Check whether the pump connected to PCB works properly.
Error Code
Water control valve fault
(Flow adjustment function)
651
(Easy-link system only)
1 PCB and flow adjustment valve fault
(Refer to section 10-11 & 10-18)
V isual inspection of Water control valve: connection/breakage of wires,
motor drive locked due to scale buildup, and/or water leakage.
Normal: 13.0 to 16 VDC between (blue-brown)
Normal: ON: 12.5 to 16.0 V / OFF: 0 to 1 V
Normal: 1 V Less than (0˚ position)
V isual inspection PCB: connection/breakage of wires and/or burn marks on
the computer board.
for exhaust of the water heater using the
Malfunction description
Malfunction description
T-H2-DV/T-H2-OS Service Manual
Diagnosis
Turn off the power
Diagnosis
Turn off the power or water supply
Diagnosis
51
CONFIDENTIAL
Ver. 1.01
Checkpoint
Cancellation method
Checkpoint
Cancellation method
Checkpoint
J