Mitsubishi Electric SUZ-SM35VA, Technical & Service Manual

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OCH779
D Check of compressor winding
Disconnect the connector between the compressor and the intelligent power module, and measure the resistance between the
compressor terminals.
<Measurement point>
Measure the resistance between the lead wires at 3 points.
BK-WH
BK-RD
WH-RD
<Judgement>
Refer to "11-4. TROUBLE CRITERION OF MAIN PARTS".
0 [Ω] ················Abnormal [short]
Infinite [Ω] ·······Abnormal [open]
NOTE
: Be sure to zero the ohmmeter before measurement.
E Check of compressor operation time
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
0 second
1 second
2 seconds
10 seconds
10 minutes
<<Judgement>>
Connect the compressor and activate the inverter. Then measure the
time until the inverter stops due to overcurrent.
<Operation method>
Start heating or cooling test run.
(TEST RUN OPERATION : Refer to 11-5 .)
<Measurement>
Measure the time from the start of compressor to the stop of
compressor due to overcurrent.
Is the resistance of thermistor normal?
(M25/35/50: Refer to 11-6-1,M60/71: 11-6-2.)
Disconnect the connector of thermistor in the outdoor P.C. board (see
below table), and measure the resistance of thermistor.
Replace the thermistor except RT64.
When RT64 is abnormal, replace the inverter
P.C. board.
Reconnect the connector of thermistor.
Turn ON the power supply and press EMERGENCY OPERATION switch.
No
Yes
F Check of outdoor thermistors
Does the unit operate for 10 minutes or more
without showing thermistor abnormality?
Yes
OK
(Cause is poor contact.)
No
Replace the inverter P.C. board.
Thermistor Symbol
Connector, Pin No.
Board
SUZ-SM35/50 SUZ-SM60
Defrost RT61 Between CN641 pin1 and pin2 Between CN671 pin1 and pin2
Inverter
P.C. board
Discharge temperature RT62 Between CN641 pin3 and pin4 Between CN671 pin3 and pin4
Fin temperature RT64 Between CN642 pin1 and pin2 Between CN673 pin1 and pin2
Ambient temperature RT65 Between CN643 pin1 and pin2 Between CN672 pin1 and pin2
Outdoor heat exchanger temperature RT68 Between CN644 pin1 and pin3 Between CN671 pin5 and pin6