When Heating Operation Does Not Operate; When Cooling Operation Does Not Operate - Mitsubishi Electric MXZ-2D33VA-E1 Service Manual

MXZ-3D54VA/3D54VA2/3D68VA/4D72VA
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 pin 1
and pin 2 at connector CN712?
Yes
Turn OFF the power supply.
Disconnect the connector CN712.
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
pin 2 at connector CN712?
Yes
Replace the outdoor control P.C. board.
OBH626H
Is there voltage 230 VAC
No
between the pin 1 and pin 3 at
connector CN711?
Replace the outdoor control P.C. board.
No
Replace the R.V. coil.
No
CN711
CN712
No
Yes
Replace the 4-way valve.
147
MXZ-3D54VA/3D54VA2/3D68VA/4D72VA
Outdoor control P.C. board
Replace the noise filter P.C. board.