33
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 10-4.
In case CN721 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 CN721 is connected.
Is there 208/230 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 208/230 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 power module
(IC700).
Turn ON the power supply and press
EMERGENCY OPERATION switch
twice (HEAT mode).
Disconnect connector between the
compressor and the power module
(IC700).
Turn ON the power supply and
press EMERGENCY OPERATION
switch once (COOL mode).
First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 10-4.
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 208/230 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 208/230 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).
MUFZ-KJ09/12
MUFZ-KJ15/18
OBH753A