Check Of Compressor; Check Of Open Phase; Troubleshooting Flow - Mitsubishi Electric Mr.Slim MUZ-FD09NA Service Manual

10-5. TROUBLESHOOTING FLOW

A How to check inverter/compressor
Disconnect the connector (CN61) between
compressor and the intelligent power module
(IPM).
Check the voltage between terminals.
Are the voltages balanced?
Check the compressor.
B 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 balance of voltage
between the terminals.
Output voltage 115 V
<< Operation method>>
Start cooling or heating operation by pressing EMERGENCY OPERATION switch on the
indoor unit. (TEST RUN OPERATION : Refer to 7-6.)
<<Measurement point>>
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.)
C Check of compressor
Refer to 10-5.

"Check of compressor

winding".
Is the compressor normal?
Refer to 10-5. "Check of compressor
operation time".
Does the compressor operate continuously?
OK.
No
Yes
Measure AC voltage between the
lead wires at 3 points.
No
Yes
No
Yes
See 10-5.

"Check of open phase".

Replace the inverter P.C. board.
See 10-5. "Check of compressor".
9-time flash
Replace the compressor.
Refer to 10-5. "Check of compressor start failure".
23
2.5-second OFF