Mitsubishi Electric MSZ-D30NA Service Manual page 178

10-5. TROUBLESHOOTING FLOW
A How to check inverter/compressor
Disconnect the connector between compressor
and the intelligent power module (IPM)/power
module (IPM) 1.
Check the voltage between terminals.
Are the voltages balanced?
Check the compressor.
B Check of open phase
● With the connector between the compressor and intelligent power module/power module 1 disconnected, activate the in-
verter 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.)
<<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
OBH549G
No
Yes
Measure AC voltage between the lead wires at 3 points.
No
Yes
No
Yes
1
Intelligent power module: MUZ-GE09/12/15/18/24NA, MUY-GE09/12/15/18/24NA
Power module: Other models
See 10-5. "Check of open phase".
Replace the inverter P.C. board.
See 10-5. "Check of compressor".
Replace the compressor.
Refer to 10-5. "Check of compressor start failure".
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