Troubleshooting Flow - Mitsubishi Electric SUZ-KA25VA5 Service Manual

10-5. TROUBLESHOOTING FLOW

A How to check inverter/compressor
Disconnect the connector between the
compressor and the intelligent power module
(KA25/35/50: IC700, KA60/71: IPM)
.
Check the voltage between terminals.
Are the voltages balanced?
Yes
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 voltage balance between the terminals.
Output voltage is 50–130 V. (The voltage may differ according to the tester.)
<< Operation method (Test run operation)>>
• For the PAR-31MAA, select "Service" → "Test Run" from the main menu to start the test run, and then select the cooling
mode.
• For details or for other information about starting the test run when using remote controllers, refer to the installation manual
for the indoor unit or the remote controller.
<<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 flashes 9 times. (KA25/35/50: Refer to 10-6-1, KA60/71: 10-6-2)
C Check of compressor
Refer to 10-5. "Check of compressor
winding".
Is the compressor normal?
Yes
Refer to 10-5. "Check of compressor
operation time".
Does the compressor operate continuously?
Yes
OK
OCH603
See 10-5.
Replace the inverter P.C. board.
No
See 10-5.
Measure AC voltage between the lead wires at 3 points.
Replace the compressor.
No
Is the compressor
operation time more than
No
10 seconds?
Check the refrigerant circuit.
26
"Check of open phase".
"Check of compressor".
Replace the compressor.
No
Yes