Mitsubishi Electric MXZ-2D33VA Service Manual page 148

• The cooling operation or the heating operation does not operate.
Check of R.V. coil
MXZ-2D33VA/2D40VA/2D42VA/2D42VA2/2D53VA/2D53VA2
MXZ-2D53VAH/2D53VAH2
1. Disconnect the lead wire leading to the compressor.
2. 3 minutes after turning ON the power supply, start EMERGENCY
OPERATION in HEAT mode.
Is there voltage of 230 VAC between pin1 and
pin2 at connector CN721?
Yes
Turn OFF the power supply. Disconnect the connector CN721.
Is there normal resistance
to R.V. coil?
(Refer to 11-5.)
Yes
Replace the 4-way valve.
1. Disconnect the lead wire leading to the compressor.
2. 3 minutes after turning ON the power supply, start EMERGENCY
OPERATION in COOL mode.
Is there voltage of 230 VAC between pin1 and
pin2 at connector CN721?
No
Replace the 4-way valve.
OBH626K
No
No
Replace the R.V. coil.
Yes
Replace the inverter P.C. board.
Replace the inverter P.C. board.
148
MXZ-2D
CN721 Inverter P.C. board