Mitsubishi Electric MXZ-2B30VA Service Manual page 81

• Fan motor does not operate or stops operating shortly after starting the operation.
Check of outdoor fan motor
Disconnect CN932 and measure the
resistance of the outdoor fan motor.
Is the resistance of outdoor fan motor
normal? (Refer to 11-5.)
No
(Fixed to either 5V or 0V DC)
Replace the outdoor fan motor.
• When the operation frequency does not go up from lowest frequency.
Check of HPS
MXZ-3B68/4B71/4B80/5B100VA
1. Disconnect the connector CN681.
2. Check the resistance of HPS 1 minute after the outdoor unit power supply was turned OFF.
Check the resistance between
each terminal.
0Ω
Reconnect CN681.
Turn ON the power supply to the indoor and outdoor unit.
3 minutes later, start EMERGENCY OPERATION.
Is HPS protection displayed
immediately after compressor
starts?
No
Normal
OBH554D
Yes
Turn ON the power supply.
Rotate the outdoor fan motor manually and measure the voltage of
CN931.
Between (+) and
Between (+) and
Between (+) and
No
Does the voltage between each terminal become 5V DC and 0V DC
repeatedly?
No
Does the outdoor fan motor rotate smoothly?
Replace the inverter P.C. board or the outdoor
electronic control P.C. board.
Infinity
Replace HPS.
Yes
Replace the electronic control P.C. board.
81
MXZ-2B
CN931
Inverter P.C. board
CN932
(-)
(-)
(-)
Yes
Yes
CN681
MXZ-3B/4B/5B
Outdoor electronic control
P.C. board
Outdoor electronic control
P.C. board