Mitsubishi Electric Mr.SLIM PLA-SM71EA Service Manual page 27

Abnormal point and detection method
Check code
Fan motor trouble
Pb
Abnormal refrigerant circuit
During Cooling, Dry, or Auto Cooling
operation, the following conditions are
regarded as failures when detected for 1
second.
a) The compressor continues to run for 30
or more seconds.
PL
b) The liquid pipe temperature or the
condenser/evaporator temperature is
75°C or more.
These detected errors will not be
cancelled until the power source is
reset.
OCH683
Cause
1 Defective fan motor
2 Defective indoor controller board
1 Abnormal operation of 4-way
valve
2 Disconnection of or leakage in
refrigerant pipes
3 Air into refrigerant piping
4 Abnormal operation (no rotation)
of indoor fan
• Defective fan motor
• Defective indoor control board.
5 Defective refrigerant circuit
(clogging)
27
Countermeasure
12 Refer to "9-6-2. DC Fan Motor (FAN
MOTOR/INDOOR CONTROLLER
BOARD)".
1 When this error occurs, be sure to replace
the 4-way valve.
2 Check refrigerant pipes for disconnection or
leakage.
3 After the recovery of refrigerant, vacuum dry
the whole refrigerant circuit.
4 Refer to section "9-6-2. DC Fan motor (FAN
MOTOR/INDOOR CONTROLLER BOARD) ".
5 Check refrigerant circuit for operation.
To avoid entry of moisture or air into
refrigerant circuit which could cause
abnormal high pressure, purge air in
refrigerant circuit or replace refrigerant.