38
Check of outdoor thermistors
• The thermistor is abnormal.
Is the resistance of the thermistor normal? (Refer to 11-5.)
Disconnect the connector in the following table.
Does the unit operate 10 minutes or more without
showing thermistor abnormality?
Replace the thermistor except RT64.
In case that RT64 is abnormal,
replace the inverter P.C. board or the
outdoor power P.C. board since RT64
is combined with this board.
Normal
Replace the inverter P.C. board, outdoor
control P.C. board or the outdoor power
P.C. board.
Yes
Yes
No
No
Reconnect the connector and disconnect the lead wire
leading to the compressor.
3 minutes after turning ON the breaker, start
EMERGENCY OPERATION.
Thermistor
Defrost
Discharge temperature
Fin temperature
Ambient temperature
Outdoor heat exchanger temperature
Symbol
RT61
RT62
RT64
RT65
RT68
Connector, Pin No.
CN641 pin1 and pin2
CN641 pin3 and pin4
CN642 pin1 and pin2
CN643 pin1 and pin2
CN644 pin1 and pin3
Inverter P.C. board
Outdoor control P.C. board
Outdoor power P.C. board
Outdoor control P.C. board
Board
Thermistor
Defrost
Discharge temperature
Fin temperature
Ambient temperature
Outdoor heat exchanger temperature
Symbol
RT61
RT62
RT64
RT65
RT68
Connector, Pin No.
CN661 pin1 and pin2
CN661 pin3 and pin4
CN9 pin1 and pin2
CN665 pin1 and pin2
CN661 pin7 and pin8
Board
MXZ-3DM50VA
MXZ-2DM40VA
OBH739A