33
F Check of compressor start failure
After the compressor is heated with a drier,
does the compressor start? 1
Replace the compressor.
Compressor start failure. Activate pre-heat control.
(Refer to 10-2. "PRE-HEAT CONTROL SETTING")
No
Yes
Does the compressor run for 10 seconds or
more after it starts?
Check the refrigerant circuit.
Check the stop valve.
Yes
No
1
Heat the compressor with
a drier for about 20 minutes.
Do not recover refrigerant
gas while heating.
Heating part
Make sure that ~ is normal.
•Electrical circuit check
. Contact of the compressor connector (Including CN61)
. Output voltage of inverter P.C. board and balance of them (See 11-5. )
. Direct current voltage between DB61(+) and (-) on the inverter P.C. board
. Voltage between outdoor terminal block S1-S2
Is the thermistor normal? (Refer to 11-6.1.)
Reconnect the connector of thermistor.
Turn ON the power supply and press EMERGENCY OPERATION switch.
No
Replace the thermistor except RT64. When RT64
is abnormal, replace the inverter P.C. board.
Does the unit operate for 10 minutes or more
without showing thermistor abnormality?
OK.
(Cause is poor contact.)
Replace the inverter P.C. board.
Thermistor
Symbol
Connector, Pin No.
Board
Defrost
RT61
Between CN641 pin 1 and pin 2
Inverter P.C. board
Discharge temperature
RT62
Between CN641 pin 3 and pin 4
Fin temperature
RT64
Between CN642 pin 1 and pin 2
Outdoor heat exchanger temperature
RT68 Between CN644 pin 1 and pin 3
MUZ-HJ50VA
only.
Yes
Yes
No
G Check of outdoor thermistors
Disconnect the connector of thermistor in the inverter P.C. board (see
below table), and measure the resistance of thermistor.
OBH648A
