Outdoor Unit - Mitsubishi Electric MU-GE50VB- E1 Service Manual

Compressor and/or outdoor fan motor does not stop.
Check of outdoor unit
Start
Turn OFF the power supply.
After 1 minute, turn ON
power supply again.
Does compressor stop?
Does outdoor fan motor stop?
Check of R.V. coil
Unit operates COOL mode even if it is set to HEAT mode.
First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.
Unit operates HEAT mode even if it is set to COOL mode.
First, measure the resistance of R.V. coil to confirm it is disconnected or is not short-circuit.
Is there 230 V AC between 3 on the
No
compressor contactor (52C) and
outdoor terminal block (TB1)?
Yes
OK
Replace the
deicer P.C. board.
No
Replace the
deicer P.C. board.
Yes
OK
Turn ON the power supply and operate
the indoor unit in HEAT mode by pressing
the EMERGENCY OPERATION switch.
After 3 minutes, does the unit
operate in COOL mode?
Is there 230 V AC between
CN721
board?
Replace the R.V. coil.
Turn ON the power supply and operate
the indoor unit in COOL mode by pressing
the EMERGENCY OPERATION switch.
After 3 minutes, does the unit
operate in HEAT mode?
Is there 230 V AC between
CN721
P.C. board?
Replace the
deicer P.C. board.
No
on the
Yes
No
OK
Yes
No
Replace the
on the deicer P.C.
deicer P.C. board
Yes
Yes
No
OK
Yes
No
on the deicer
Replace the R.V. coil.
Yes
19
Rectify the connecting wire.