Mitsubishi Electric MXZ-2C30VA, Service Manual

Page: 104 / 396

104
How to check inverter/compressor
• When heating, room does not get warm.
• When cooling, room does not get cool.
Disconnect the terminal of the compressor or the connector (CNMC) between compressor and
the inverter P.C. board/the outdoor power P.C. board. 3 minutes after turning ON the
power supply, start EMERGENCY OPERATION.
Is output balanced?
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
Measure the voltage between each lead
wire leading to the compressor.
U (BLK) - V (WHT)
V (WHT) - W (RED)
W (RED) - U (BLK)
Output voltage 50V-250V
Is proper output voltage detected?
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.)
Is the input voltage to the electronic control
P.C. board/the control P.C. board/the outdoor
control P.C. board 370V or more (
MXZ-3C/4C/
5C
)/350V or more (
MXZ-6C
) ?
Reconnect the lead wire of compressor, and turn ON
the power supply to indoor and outdoor unit.
3 minutes later, start EMERGENCY OPERATION.
Replace the
compressor.
Replace the power board (
MXZ-3C/4C/
5C/6C120
)/outdoor power P.C. board
(
MXZ-6C122
).
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.
No
1 2
No
Yes
Yes
Yes
No
Yes
No
Yes
(MXZ-2C)
(
MXZ-3C/4C/5C/6C
)
OBH584G