Check Of Open Phase; Check Of Compressor; Check Of Compressor Winding - Mitsubishi Electric Mr.Slim MUZ-GC25NA - C1 Service Manual

B Check of open phase
MUZ-GC25/35NA MUZ-GC50NA-
● 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 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 6-3.)
<<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 inverter P.C. board fl ashes 9 times. (Refer to 9-6.1.)
C Check of compressor
MUZ-GC25/35NA MUZ-GC50NA-
Refer to 9-5.

"Check of compressor

winding". Is the compressor normal?
Refer to 9-5. "Check of compressor
operation time". Does the compressor
operate continuously?
OK.
D Check of compressor winding
MUZ-GC25/35NA
● Disconnect the connector (CN61) between the compressor and intelligent power module, and measure the resistance be-
tween the compressor terminals.
<<Measurement point>>
At 3 points
BLK-WHT
BLK-RED
WHT-RED
<<Judgement>>
Refer to 9-4.
0[Ω] ················Abnormal [short]
Infinite[Ω] ·······Abnormal [open]
NOTE: Be sure to zero the ohmmeter before measurement.
C2
Measure AC voltage between the
lead wires at 3 points.
C2
No
Yes
No
Yes
Measure the resistance between the lead wires at 3 points.
Replace the compressor.
Refer to 9-5. "Check of compressor start failure".
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