32
H Check of R.V. coil
First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 11-4.
In case CN721 is not connected or R.V. coil is open, voltage is generated between the terminal pins of the connector
although any signal is not being transmitted to R.V. coil.
Check if CN721 is connected.
Is there 230 VAC between CN721 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 CN721 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 intelligent
power module.
Turn ON the power supply and
press EMERGENCY OPERATION
switch twice (HEAT mode).
Disconnect connector between
the compressor and the intelligent
power module.
Turn ON the power supply and
press EMERGENCY OPERATION
switch once (COOL mode).
[SUZ-KA25/35/50VA3.TH]
Is the resistance of thermistor normal?
(Refer to 11-6-1.)
Disconnect the connector of thermistor in the outdoor P.C. board (see
below table), and measure the resistance of thermistor.
Replace the thermistor except RT64.
When RT64 is abnormal, replace the inverter
P.C. board.
Reconnect the connector of thermistor.
Turn ON the power supply and press EMERGENCY OPERATION switch.
No
Yes
G Check of outdoor thermistors
Does the unit operate for 10 minutes or more
without showing thermistor abnormality?
Yes
OK.
(Cause is poor contact.)
No
Replace the inverter P.C. board.
Thermistor
Symbol
Connector, Pin No.
Board
Defrost
RT61
Between CN641 pin1 and pin2
Inverter P.C. board
Discharge temperature
RT62
Between CN641 pin3 and pin4
Fin temperature
RT64
Between CN642 pin1 and pin2
Ambient temperature
RT65
Between CN643 pin1 and pin2
Outdoor heat exchanger temperature
RT68
Between CN644 pin1 and pin3
OCH530
