Mitsubishi Electric HP120TNU-A Service Handbook page 287

[8-10 Troubleshooting Inverter Problems ]
8-10-2 Checking the Inverter Board Error Detection Circuit
Items to be checked
(1) Stop the unit.
Remove power supply.
(2) Disconnect the inverter
output wires from the
compressor terminals (U,
*1
V, W).
(3) Apply power supply.
(4) Put the outdoor unit into
operation.
*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.
8-10-3 Checking the Compressor for Ground Fault and Coil Resistance Problems
Items to be checked
Disconnect the compressor wir-
ing, and check the compressor
Meg, and coil resistance.
46
- chapter 8
Phenomena
1) Overcurrent error
Error code: 4250
Detail code: No. 101, 104, 105, 106, and
107
2) Logic error
Error code: 4220
Detail code: No. 111
3) ACCT sensor circuit failure
Error code: 5301
Detail code: No.117
4) IPM open
Error code: 5301
Detail code: No.119
Phenomena
1) Compressor Meg failure
Error if less than 1 M .
2) Compressor coil resistance failure
Coil resistance value
HP72 model
0.078 (YNU), 0.192
HP96, HP120 models
0.087 (YNU), 0.219
Replace the INV board.
Replace the INV board.
Replace the INV board.
Normal
Check that there is no liquid refrigerant
in the compressor.
If there is none, replace the compres-
sor.
Replace the compressor.
(TNU)
(TNU)
Remedy
Remedy
HWE18220_GB