Mitsubishi Electric MXZ-2D33VA Service Manual page 142

• In heating, the room does not get warm.
• In cooling, the room does not get cool.
How to check inverter/compressor
Disconnect the connector (CNMC) between the inverter P.C. board/the
outdoor control P.C. board and compressor, or disconnet the terminal of the
compressor.
3 minutes after turning ON the power supply, start EMERGENCY OPERATION.
Measure the voltage between each lead
wire leading to the compressor.
U (BLK) - V (WHT)
V (WHT) - W (RED)
W (RED) - U (BLK)
Is there voltage of 50 VAC - 250 VAC? * 1, * 2
Yes
Is output balanced?
Yes
(Except MXZ-2D)
Is the input voltage to the outdoor control
P.C. board 370 VDC or more?
Yes
Turn OFF the power supply, and measure the
compressor winding resistance between the
compressor terminals.
Is there resistance between each
terminal normal? (Refer to 11-5.)
Yes
Reconnect the lead wire of compressor.
3 minutes after turning ON the power supply,
start EMERGENCY OPERATION.
Clarify the causes by counting time until the
inverter stops.
0 to 10 seconds: compressor layer short
10 to 60 seconds: compressor lock
60 seconds to 5minutes: refrigerant circuit defective
5 minutes or more: normal
OBH626K
No
No
No
No
Replace the inverter P.C. board or
the outdoor power P.C. board.
Replace the outdoor power P.C. board.
Replace the compressor.
* 1 After the outdoor fan starts running, wait for 1 minute or
more before measuring the voltage.
The output voltage values have the tolerance of ± 20%.
* 2 The output differs depending on the capacity or the
number of indoor units to be operated.
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