520 Indoor / 520 Outdoor Service Manual
Ver. 1.00
49
CONFIDENTIAL
Error Code
Malfunction description
Cancellation method
611
Fan motor fault
Turn off the power or water supply
Diagnosis
Checkpoint
1 PCB and fan motor fault (Refer to section 10-3 & 10-18)
Visual 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 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.
G1
Error Code
Malfunction description
Cancellation method
621
Exhaust fan motor fault (520 Indoor only)
Turn off the power or water supply
Diagnosis
Checkpoint
1 PCB and fan motor for exhaust fault
(Refer to section 10-4 & 10-18)
Visual 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)
Just before the unit begins operation, the signal to operate FM for exhaust
is still OFF. But at that time, if over 1,000rpm of FM speed is detected for 20
sec, 621 error code will display.
If less than 1,000rpm of FM for exhaust speed is detected when the signal
to operate FM is ON, 621 error code will display.
If over 300 rpm of FM for exhaust gas speed difference between the target
speed signal and the actual speed signal from FM is detected, 621 error
code will display.
G2
