Mitsubishi Electric MSZ-LN-VG Series Service Manual page 116

• 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-2F33VF2/2F42VF2/2F53VF2
MXZ-2F33VF3/2F42VF3/2F53VF3
MXZ-2F53VFH
MXZ-2F53VFH2
MXZ-2F53VFH3
Thermistor
Defrost
Discharge temperature
Fin temperature
Ambient temperature
Outdoor heat exchanger temperature
MXZ-3F54VF/3F68VF/4F72VF
MXZ-3F54VF2/3F68VF2/4F72VF2/4F80VF2
MXZ-3F54VF3/3F68VF3/4F72VF3/4F80VF3
Thermistor
Defrost
Discharge temperature
Outdoor heat exchanger temperature
Ambient temperature
Fin temperature
OBH790D
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.
RT61 CN641 pin1 and pin2
RT62 CN641 pin3 and pin4
RT64 CN642 pin1 and pin2
RT65 CN643 pin1 and pin2
RT68 CN644 pin1 and pin3
Symbol Connector, Pin No.
RT61 Between CNTH1 pin1 and pin2
RT62 Between CNTH1 pin3 and pin4
RT68 Between CNTH1 pin7 and pin8
RT65 Between CNTH2 pin1 and pin2
RT64 Between CN171 pin1 and pin2
116
Board
Inverter P.C. board
Board
Outdoor control P.C. board
Outdoor power P.C. board