MITSUBISHI ELECTRIC MUY-GE09NA - Manual (Page 29)

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10-5. TROUBLESHOOTING FLOW
Are the voltages balanced?
Disconnect the connector (CN61) between
compressor and the intelligent power module
(IPM).
Replace the inverter P.C. board.
Check the voltage between terminals.
Check the compressor. See 10-5. “Check of compressor”.
No
Yes
See 10-5. “Check of open phase”.
● With the connector between the compressor and the intelligent power module disconnected, activate the inverter and check if
the inverter is normal by measuring the voltage balance between the terminals.
Output voltage is 50 - 130 V. (The voltage may differ according to the tester.)
<< Operation method>>
Start cooling or heating operation by pressing EMERGENCY OPERATION switch on the indoor unit. (TEST RUN OPERA-
TION: Refer to 7-6.)
<>
at 3 points
BLK (U) - WHT (V)
BLK (U) - RED (W)
WHT(V) - RED (W)
NOTE : 1. Output voltage varies according to power supply voltage.
2. Measure the voltage by analog type tester.
3. During this check, LED of the inverter P.C. board fl ashes 9 times. (Refer to 10-6.1.)
Measure AC voltage between the lead wires at 3 points.
Refer to 10-5. “Check of compressor
operation time”.
Does the compressor operate continuously?
Refer to 10-5. “Check of compressor start failure”.
OK.
No
Yes
Refer to 10-5. “Check of compressor
winding”.
Is the compressor normal?
Replace the compressor.
No
Yes
B Check of open phase
A How to check inverter/compressor
C Check of compressor