34
Check of R.V. coil
C
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 (52C) and
N
on the
outdoor terminal block?
Yes
Replace the
compressor contactor(52C).
No
Rectify the connecting
wire.
After 3 minutes, is there
230V AC between CN721
1
-
3
on the deicer P.C. board?
Replace the
deicer P.C. board.
Yes
No
Replace the R.V. coil.
Disconnect the TAB52 on the deicer P.C. board.
Turn ON the power supply and operate
the indoor unit in HEAT mode by pressing
the EMERGENCY OPERATION switch.
Unit operates COOL mode even if it is set to HEAT mode.
MUH-A18WV
w
First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.
MUH-A24WV
MUH-A30WV
B
B
Check of outdoor unit
Does compressor stop?
No
Yes
Is there 230V AC between 3 on the
compressor contactor (52C) and
N
on the
outdoor terminal block (TB1)?
Replace the
deicer P.C. board.
Yes
OK
No
Does outdoor fan motor stop?
Replace the
deicer P.C. board.
Yes
OK
No
Rectify the connecting wire.
Turn OFF the power supply.
After 1 minute, turn ON
power supply again.
Compressor and/or outdoor fan motor doesn’t stop.
OB322-2.qxp 03.11.13 4:08 PM Page 34
Summary of Contents for MUH-A18WV
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