Mitsubishi Electric City Multi CMH-WM250V-A, Service Handbook

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[8-10 Troubleshooting Inverter Problems ]
BS_08_E chapter 8 -
49
8 Troub
le
sho
oting Bas
ed on Ob
ser
ved
Sy
mp
toms
8-10-11 Checking the Pump Motor for Ground Fault and Coil Resistance Problems
8-10-12 Checking the Error-Detection Circuit on the Pump INV Board (Without load)
8-10-13 Checking the Pump INV Board for Damage (Without load)
Items to be checked Phenomena Remedy
Remove pump motor winding. Check
insulation resistance and coil resis-
tance. 1) Pump motor insulation failure.
If < 1 M
Ω
, Defect.
Replace the pump
2) Pump motor wire failure.
Target coil resistance: Approx. 10
Ω
.
(Changes with temperature)
Replace the pump
Items to be checked Phenomena Remedy
<INV32> 1) IPM/overcurrent cut-off error occurs.
Check code: 4250
Detail code: 101, 104, 105, 106, 107,
128 Replace the INV board.
1) Disconnect the inverter output
wiring from the INV board termi-
nals (SC-U, SC-V, SC-W). 2) Logic error occurs.
Check code: 4220
Detail code: 111 Replace the INV board.
2) Operate the outdoor unit and
the hydro unit. 3) Sensor-related circuit error occurs.
Check code: 5301
Detail code: 117, 127 Replace the INV board.
4) Open-circuited IPM error occurs.
Check code: 5301
Detail code: 119 Normal
Items to be checked Phenomena Remedy
<INV32> 1) Inverter-related error is detected. Set SW 1-1 on the INV board to
OFF, and go to [8-10-12 Checking
the Error-Detection Circuit on the
Pump INV Board (Without load)].
1) Disconnect the inverter output
wiring from the INV board termi-
nals (SC-U, SC-V, SC-W). 2) Inverter voltage is not output. Replace the INV board.
2) Set SW 1-1 on the INV board to
ON. 3) Line voltage imbalance of at least 5%
or 5 V occurs. Replace the INV board.
3) Operate the outdoor unit and
the hydro unit.
Wait until the inverter output fre-
quency is stabilized, and then
check the inverter output volt-
age. 4) No line voltage imbalance exists. Normal
*Check the voltage, and set SW 1-1
on the INV board to OFF.
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