520 Indoor / 520 Outdoor Service Manual
Ver. 1.00
50
CONFIDENTIAL
Error Code
Diagnosis
Checkpoint
621
Verify fan motor speed
for exhaust of the water heater using the
"diagnostics mode" of the 520 models computer board or the 9007603005
temperature remote controller.
See the "12-1. How to diagnose the water heater using the 9007603005”.
Visual inspection of PCB: connection/breakage of wires and/or burn marks
on the computer board.
Error Code
Malfunction description
Cancellation method
631
Abnormal External pump
Turn off the power
Diagnosis
Checkpoint
1 Check whether the pump connected to PCB works properly.
Error Code
Malfunction description
Cancellation method
651
Water control valve fault
(Flow adjustment function)
(Easy-link system only)
Turn off the power or water supply
Diagnosis
Checkpoint
1 PCB and flow adjustment valve fault
(Refer to section 10-11 & 10-18)
Visual 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)
Visual inspection PCB: connection/breakage of wires and/or burn marks on
the computer board.
J