Mitsubishi Electric SUZ-KA25VA2 Technical & Service Manual page 35

D Check of compressor winding
Disconnect the connector 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
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 11-5 B.)
<<Measurement>>
Measure the time from the start of compressor to the stop of
compressor due to overcurrent.
F Check of outdoor thermistors
Disconnect the connector of thermistor in the outdoor P.C. board (see
below table), and measure the resistance of thermistor.
Is the thermistor normal?
(Refer to 11-6-1. or 11-6-2. )
Reconnect the connector of thermistor.
Turn ON the power supply and press EMERGENCY OPERATION switch.
Does the unit operate for 10 minutes or more
without showing thermistor abnormality?
OK.
(Cause is poor contact.)
Thermistor
Defrost
Discharge temperature
Fin temperature
Ambient temperature
Outdoor heat exchanger temperature
OCH472A
No
Yes
No
Yes
Symbol Connector, Pin No.
RT61 Between CN641 pin1 and pin2
RT62 Between CN641 pin3 and pin4
RT64 Between CN642 pin1 and pin2
RT65 Between CN643 pin1 and pin2
RT68 Between CN644 pin1 and pin3
35
[SUZ-KA25/35/50VA2.TH]
<<Judgement>>
0 second
Compressor starts
1 second
Abnormal
(IPM failure)
(Compressor winding short)
2 seconds
Abnormal
(Compressor lock out)
(Starting defect)
Abnormal
(Poor contact,)
(Outdoor P.C. board defect)
10 seconds
(Disconnected connector)
Abnormal
(Refrigerant circuit defect)
(Closed valve)
10 minutes
Normal
Replace the thermistor except RT64.
When RT64 is abnormal, replace the inverter P.C.
board or the outdoor power board.
Replace the inverter P.C. board
or the outdoor power board.
Inverter P.C. board
Board