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

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[8-10 Troubleshooting Inverter Problems ]
42
- chapter 8 BS_08_E
8 Troub
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8-10-2 Checking the Inverter Board Error Detection Circuit
*1 Output voltage is present at the inverter output wiring terminal. To avoid short-circuiting and ground fault, do not let the
terminal come in contact with the unit or the compressor, and use caution not to damage the terminal.
*2 Compressors on P200, P250, and P300 models are located in the back of the MAIN BOX. To disconnect the inverter output
wiring, move the MAIN BOX out of the way first, and then disconnect the wiring from the terminal on the compressor. Refer
to [8-13-1 Ensuring Maintenance Space (Preparation for the Maintenance of Refrigerant Circuit Parts)] for how to move the
MAIN BOX.
8-10-3 Checking the Compressor for Ground Fault and Coil Resistance Problems
Items to be checked Phenomena Remedy
(1) Stop the unit.
Remove power supply. 1) Overcurrent error
Error code: 4250
Detail code: No. 101, 104, 105, 106, and
107 Replace the INV board.
(2) Disconnect the inverter
output wires from the
compressor terminals (U,
V, W).
*1
2) Logic error
Error code: 4220
Detail code: No. 111 Replace the INV board.
(3) Apply power supply. 3) ACCT sensor circuit failure
Error code: 5301
Detail code: No.117 Replace the INV board.
(4) Put the outdoor unit into
operation. 4) IPM open
Error code: 5301
Detail code: No.119 Normal
Items to be checked Phenomena Remedy
Disconnect the compressor wir-
ing, and check the compressor
Meg, and coil resistance. 1) Compressor Meg failure
Error if less than 1 M
Ω
.
Check that there is no liquid refrigerant
in the compressor.
If there is none, replace the compres-
sor.
2) Compressor coil resistance failure
Coil resistance value of 0.192
Ω
(20°C [68°F]): (E)M200 to (E)M350 mod-
els
Coil resistance value of 0.219
Ω
(20°C [68°F]): (E)M400 to (E)M500 mod-
el
Replace the compressor.
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