Mitsubishi Electric MXZ-2D33VA Service Manual page 143

• The thermistor is abnormal.
Check of outdoor thermistors
Disconnect the connector in the following table.
Is the resistance of the thermistor normal? (Refer to 11-5.)
Yes
Reconnect the connector 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-2D33VA/2D40VA/2D42VA/2D42VA2/2D53VA/2D53VA2
MXZ-2D53VAH/2D53VAH2
Thermistor
Defrost
Discharge temperature
Fin temperature
Ambient temperature
Outdoor heat exchanger temperature
MXZ-3D54/3D68/4D72VA
MXZ-3D54VA2
Thermistor
Defrost
Discharge temperature
Fin temperature
Ambient temperature
Outdoor heat exchanger temperature
MXZ-4D83/5D102VA
Thermistor
Defrost
Discharge temperature
Fin temperature
Ambient temperature
Outdoor heat exchanger temperature
MXZ-6D122VA
Thermistor
Defrost
Discharge temperature
Outdoor heat exchanger temperature
Ambient temperature
Fin temperature
OBH626K
Replace the thermistor except RT64.
In case that RT64 is abnormal,
No
replace the inverter P.C. board or the
outdoor power P.C. board since RT64
is combined with this board.
Replace the inverter P.C. board, outdoor
No
control P.C. board or the outdoor power
P.C. board.
Symbol Connector, Pin No.
RT61 CN641 pin1 and pin2
CN641 pin3 and pin4
RT62
RT64 CN642 pin1 and pin2
CN643 pin1 and pin2
RT65
RT68 CN644 pin1 and pin3
Symbol Connector, Pin No.
CN661 pin1 and pin2
RT61
RT62 CN661 pin3 and pin4
RT64 CN9 pin1 and pin2
RT65 CN665 pin1 and pin2
RT68 CN661 pin7 and pin8
Symbol Connector, Pin No.
CN661 pin1 and pin2
RT61
RT62 CN661 pin3 and pin4
CN3 pin1 and pin2
RT64
RT65 CN661 pin7 and pin8
CN663 pin1 and pin2
RT68
Symbol Connector, Pin No.
Between CNTH1 pin1 and pin2
RT61
RT62 Between CNTH1 pin3 and pin4
Between CNTH1 pin7 and pin8
RT68
RT65 Between CNTH2 pin1 and pin2
Between CN171 pin1 and pin2
RT64
143
Board
Inverter P.C. board
Board
Outdoor control P.C. board
Outdoor power P.C. board
Outdoor control P.C. board
Board
Outdoor control P.C. board
Outdoor power P.C. board
Outdoor control P.C. board
Board
Outdoor control P.C. board
Outdoor power P.C. board