Mitsubishi Electric MXZ-2A30VA - E1 Service Manual page 135

• 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 13-7.)
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-2A30/2A40/2A52
Thermistor
Defrost
Discharge temperature
Outdoor heat exchanger temperature
Fin temperature
Ambient temperature
MXZ-3A54/4A71/4A80/5A100
Thermistor
Defrost
Discharge temperature
Outdoor heat exchanger temperature
Gas pipe temperature (Unit A)
Gas pipe temperature (Unit B)
Gas pipe temperature (Unit C)
Gas pipe temperature (Unit D)
Ambient temperature
Fin temperature
Except MXZ-3A54VA-
Symbol
RT61
RT62
RT68
RT64
RT65
Symbol
RT61
RT62
RT68
RT6A
RT6B
RT6C
RT6D
RT65
RT64
, , , , MXZ-4A71VA-
E4 E5 E6 E7
Abnormal
No
Replace the inverter P.C. board,
the outdoor electronic control P.C. board,
or the outdoor power board.
Connector, Pin No.
Between CN661 pin1 and pin2
Between CN661 pin3 and pin4
Between CN661 pin5 and pin6
Between CN662 pin1 and pin2
Between CN663 pin1 and pin2
Connector, Pin No.
Between CN661 pin1 and pin2
Between CN661 pin3 and pin4
Between CN661 pin7 and pin8
Between CN662 pin1 and pin2
Between CN662 pin3 and pin4
Between CN662 pin5 and pin6
Between CN662 pin7 and pin8
Between CN663 pin1 and pin2
Between CN3 pin1 and pin2
, , , , MXZ-4A80VA-
E4 E5 E6 E7
135
Replace the thermistor except RT64.
In case that RT64 is abnormal,
replace the inverter P.C. board or
the outdoor power board since RT64
is combined with the inverter P.C.
board or the outdoor power board.
Board
Inverter P.C. board
Board
Outdoor electronic control P.C. board
Outdoor power board
and MXZ-5A100VA.
E2