25
Check of outdoor unit
C
Compressor and/or outdoor fan motor doesn’t stop.
After 30 seconds,
does compressor stop?
No
Yes
Is there 230V AC between
A1-A2 on the compressor
contactor(52C)?
Replace the
deicer P.C. board.
Yes
1
Turn OFF the power supply.
2
After 30 seconds, turn ON the power supply again.
3
Operate the unit in COOL or HEAT mode by
pressing the EMERGENCY OPERATION switch.
4
Operate the unit for 1 minute or more and stop it by
pressing the EMERGENCY OPERATION switch again.
Ok
No
After 30 seconds, does
outdoor fan motor stop?
Replace the
deicer P.C. board.
Yes
Ok
No
Is there 230V AC between
2/T1 on the compressor
contactor and
N
on the
outdoor terminal block?
Yes
Replace the compressor
contactor(52C).
No
Make the connection
of wiring correct.
Check of R.V. coil
D
After 3 minutes, does the unit
operate in COOL mode?
OK
Yes
Yes
No
After 3 minutes, does the unit
operate in HEAT mode?
Ok
No
Replace the
deicer P.C. board
No
Replace the R.V. coil.
Disconnect the TAB52 on the deicer P.C. board. (MUCFH-A24WV)
Turn ON the power supply and operate the indoor unit in HEAT mode
by pressing the EMERGENCY OPERATION switch.
Replace the
deicer P.C. board.
Yes
Yes
No
Replace the R.V. coil.
Is there 230V AC between
CN721
1
–
2
(MUCFH-A18WV)/
CN721
1
–
3
(MUCFH-A24WV)
on the deicer P.C. board?
Disconnect the TAB52 on the deicer P.C. board. (MUCFH-A24WV)
Turn ON the power supply and operate the indoor unit in COOL mode
by pressing the EMERGENCY OPERATION switch.
Is there 230V AC between
CN721
1
–
2
(MUCFH-A18WV)/
CN721
1
–
3
(MUCFH-A24WV)
on the deicer P.C. board?
Unit operates COOL mode even if it is set to HEAT mode.
w
First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.
w
First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.
Check of R.V. coil
D
Unit operates HEAT mode even if it is set to COOL mode.
OB337B--1.qxp 05.7.6 11:00 AM Page 25
