Mitsubishi Electric MSZ-D30NA Service Manual page 181

Unit operates HEAT mode even if it is set to COOL mode.
Disconnect connector between the
compressor and intelligent power
module/ power module 1.
Turn ON the power supply and press
EMERGENCY OPERATION switch
once (COOL mode).
I Check of outdoor fan motor
Disconnect the connectors CN931 and CN932
from the inverter P.C. board.Check the connec-
tion between the connector CN931 and CN932.
Is the resistance between each ter-
minal of outdoor fan motor normal?
(Refer to 10-4.)
No
Replace the outdoor fan motor.
OBH549G
1
Intelligent power module: MUZ-GE09/12/15/18/24NA, MUY-GE09/12/15/18/24NA
Power module: Other models
Yes
(Fixed to either 5 or 0 VDC)
Is there 230 VAC between CN721 (MUZ-
GE09/12/15/18)/CN602 (MUZ-GE24)
on the inverter P.C. board 3 minutes after
the power supply is turned ON?
No
Replace the 4-way valve.
Disconnect CN932 from the inverter P.C. board, and turn on the
power supply.
Rotate the outdoor fan motor manually and measure the voltage
of CN931.
Between 1(+) and 5(-)
Between 2(+) and 5(-)
Between 3(+) and 5(-)
Does the voltage between each terminal become 5 and 0
No
VDC repeatedly?
Does the outdoor fan motor rotate smoothly?
No
Replace the inverter P.C. board.
55
and Replace the inverter
Yes
P.C. board.
Yes
Yes