Mitsubishi Electric SEZ-KD VA Series, Service Manual

Page: 99 / 301

99
How to check inverter/compressor
No
No
Yes
Yes
No
Yes
No
Yes
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 breaker, start EMERGENCY OPERATION.
Is output balanced?
Replace the inverter P.C. board or
the outdoor power P.C. board.
(Except MXZ-2D )
Is the input voltage to the outdoor control
P.C. board 370 VDC or more?
Replace the outdoor power P.C. board.
Replace the compressor.
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
Turn OFF the breaker, and measure the
compressor winding resistance between the
compressor terminals.
Is there resistance between each
terminal normal? (Refer to 11-5.)
Reconnect the lead wire of compressor.
3 minutes after turning ON the breaker,
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
* 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.
• In heating, the room does not get warm.
• In cooling, the room does not get cool.
OBH626E