Mitsubishi Electric MUZ-FD25VABH - E1 Service Manual page 39

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D Check of compressor winding
MUZ-FD25/35
●Disconnect the connector (CN61) between the compressor and intelligent power module, and measure the resistance between
the compressor terminals.
<<Measurement point>>
at 3 points
BLK-WHT
Measure the resistance between the lead wires at 3 points.
BLK-RED
WHT-RED
<<Judgement>>
Refer to 11-4.
0 [Ω] ················Abnormal [short]
Infinite [Ω] ·······Abnormal [open]
NOTE: Be sure to zero the ohmmeter before measurement.
E Check of compressor operation time
MUZ-FD25/35
● Connect the compressor and activate the inverter. Then measure
the time until the inverter stops due to over current.
<<Operation method>>
Start heating or cooling operation by pressing EMERGENCY
OPERATION switch on the indoor unit.
(TEST RUN OPERATION : Refer to 8-3.)
<<Measurement>>
Measure the time from the start of compressor to the stop of
compressor due to overcurrent.
F Check of compressor start failure
MUZ-FD25/35
Confi rm that ~ is normal.
•Electrical circuit check
. Contact of the compressor connector (Including CN61)
. Output voltage of inverter P.C. board and balance of them (See 11-5. )
. Direct current voltage between DB61(+) and (-) on the inverter P.C. board
. Voltage between outdoor terminal block S1-S2
Does the compressor run for 10 seconds or
more after it starts?
No
After the compressor is heated with a drier,
does the compressor start?
Yes
Compressor start failure. Activate pre-heat control.
(Refer to 10-2. "PRE-HEAT CONTROL SETTING")
Check the refrigerant circuit.
Yes
Check the stop valve.
Replace the compressor.
No
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<<Judgement>>
0 second
1 second
2 seconds
10 seconds
10 minutes
39
Compressor starts
Abnormal
(IPM failure)
(Compressor winding short)
Abnormal
(Compressor lock out)
(Starting defect)
Abnormal
(Poor contact,)
(Outdoor P.C. board defect)
(Disconnected connector)
Abnormal
(Refrigerant circuit defect)
(Closed valve)
Normal
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Heat the compressor with
a drier for about 20 minutes.
Do not recover refrigerant
gas while heating.
Heating part