Check Of Outdoor Thermistors - Mitsubishi Electric MXZ-2F33VF-E1 Service Manual

• When thermistor is abnormal.

Check of outdoor thermistors

Disconnect the connector in the following table and
measure the resistance of the thermistor to check
whether the thermistor is normal or not. (Refer to 12-7.)
Normal
Reconnect the connector in the following table and
disconnect the lead wire leading to the compressor.
3 minutes after turning ON the power supply,
start EMERGENCY OPERATION.
Does the unit operate 10 minutes or more without
showing thermistor abnormality?
Yes
Normal
MXZ-2F33VF/2F42VF/2F53VF
MXZ-2F53VFH
Thermistor
Defrost
Discharge temperature
Fin temperature
Ambient temperature
Outdoor heat exchanger temperature
MXZ-3F54VF/3F68VF/4F72VF
Thermistor
Defrost
Discharge temperature
Outdoor heat exchanger temperature
Ambient temperature
Fin temperature
OBH790
Replace the thermistor except RT64.
Abnormal
If RT64 is abnormal, replace the outdoor power
P.C. board since RT64 is combined with this board.
No
Replace the outdoor control P.C. board or the
outdoor power P.C. board.
Symbol Connector, Pin No.
CN641 pin1 and pin2
RT61
RT62 CN641 pin3 and pin4
CN642 pin1 and pin2
RT64
CN643 pin1 and pin2
RT65
RT68 CN644 pin1 and pin3
Symbol Connector, Pin No.
RT61 Between CNTH1 pin1 and pin2
Between CNTH1 pin3 and pin4
RT62
Between CNTH1 pin7 and pin8
RT68
RT65 Between CNTH2 pin1 and pin2
RT64 Between CN171 pin1 and pin2
78
Board
Inverter P.C. board
Board
Outdoor control P.C. board
Outdoor power P.C. board