Mitsubishi Electric Mr.SLIM PCA-RP50KAQ Service Manual page 29

Abnormal point and detection method
Error Code
Abnormal refrigerant circuit
During Cooling, Dry, or Auto Cooling
operation, when the following are
regarded as failures when detected for
one second.
a) The compressor continues to run for 30
PL or more seconds.
b) The liquid pipe temperature or the
condense/evaporator temperature is
75°C or more.
* These detected errors will not be
cancelled until the power source is
reset.
OCH491C
Cause
Abnormal operation of 4-way
valve
Disconnection of or leakage in
refrigerant pipes
Air into refrigerant piping
Abnormal operation (no rotation)
of indoor fan
· Defective fan motor.
· Defective indoor control board.
Defective refrigerant circuit
(clogging)
29
Countermeasure
When this error occurs, be sure to replace
the 4-way valve.
Check refrigerant pipes for disconnection or
leakage.
After the recovery of refrigerant, vacuum dry
the whole refrigerant circuit.
Refer to section 10-6-2.
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.