Checking The Inverter Board Error Detection Circuit; Checking The Compressor For Ground Fault And Coil Resistance Problems; Checking The Inverter For Damage At No-Load - Mitsubishi Electric R410A Service Handbook

[8-10 Troubleshooting Inverter Problems (YLMU) ]
8-10-2

Checking the Inverter Board Error Detection Circuit

Items to be checked
(1) Remove power supply.
(2) Disconnect the inverter
output wire from the ter-
minals of the INV board
(SC-U, SC-V, SC-W).
(3) Apply power supply.
(4) Put the outdoor unit into
operation.
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.
8-10-4

Checking the Inverter for Damage at No-Load

Items to be checked
(1) Remove power supply.
(2) Disconnect the inverter
output wire from the ter-
minals of the INV board
(SC-U, SC-V, SC-W).
(3) Disconnect the short-cir-
cuit connector from CN6
on the INV board.
(4) Apply power supply.
(5) Put the outdoor unit into
operation.
Check the inverter output
voltage after the inverter
output frequency has sta-
bilized.
HWE14080
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 Mohm.
2) Compressor coil resistance failure
Coil resistance value of 0.71 ohm
(20°C [68°F]): P72 model
Coil resistance value of 0.32 ohm
(20°C [68°F]): P96 - P144 models
Phenomena
1) Inverter-related problems are detected.
2) Inverter voltage is not output at the termi-
nals (SC-U, SC-V, and SC-W)
3) There is an voltage imbalance between
the wires.
Greater than 5% imbalance or 5V
4) There is no voltage imbalance between
the wires.
- 278 -
Remedy
Replace the INV board.
Replace the INV board.
Replace the INV board.
Normal
Remedy
Check that there is no liquid refrigerant
in the compressor.
If there is none, replace the compres-
sor.
Replace the compressor.
Remedy
Connect the short-circuit connector to
CN6, and go to section 8-10-2.
Replace the INV board.
Replace the INV board.
Normal
*Reconnect the short-circuit connector
to CN6 after checking the voltage.
GB