30
G Check of outdoor thermistors
H Check of R.V. coil
Replace the thermistor except RT64.
When RT64 is abnormal, replace the inverter P.C.
board.
Replace the inverter P.C. board.
No
No
Is the resistance of thermistor normal?
(Refer to 11-6.1.)
Reconnect the connector of thermistor.
Turn ON the power supply and press EMERGENCY OPERATION switch.
Does the unit operate for 10 minutes or more
without showing thermistor abnormality?
OK.
(Cause is poor contact.)
Yes
Yes
Disconnect the connector of thermistor in the outdoor P.C. board (see
below table), and measure the resistance of thermistor.
Thermistor
Symbol
Connector, Pin No.
Board
Defrost
RT61
Between CN671 pin1 and pin2
Inverter P.C. board
Discharge temperature
RT62
Between CN671 pin3 and pin4
Fin temperature
RT64
Between CN673 pin1 and pin2
Ambient temperature
RT65
Between CN672 pin1 and pin2
Outdoor heat exchanger temperature RT68
Between CN671 pin5 and pin6
First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 11-4.
In case CN602 is disconnected or R.V. coil is open, voltage is generated between the terminal pins of the connector
although no signal is being transmitted to R.V. coil.
Check if CN602 is connected.
Is there 230 VAC between CN602 and
on the inverter P.C. board 3 minutes
after the power supply is turned ON?
No
Yes
Replace the inverter
P.C. board.
Replace the 4-way valve.
Unit operates COOL mode even if it is set to HEAT mode.
Is there 230 VAC between CN602 and
on the inverter P.C. board 3 minutes
after the power supply is turned ON?
Yes
No
Replace the inverter
P.C. board.
Replace the 4-way valve.
Unit operates HEAT mode even if it is set to COOL mode.
Disconnect connector between the
compressor and the IGBT module
(IC700).
Turn ON the power supply and press
EMERGENCY OPERATION switch
twice (HEAT mode).
Disconnect connector between the
compressor and the IGBT module
(IC700).
Turn ON the power supply and
press EMERGENCY OPERATION
switch once (COOL mode).
OBH635