Midea M2OC-18HFN1-M, Service Manual

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9.4.2.11 P3(Current protection of compressor) error diagnosis and solution.
Error Code P3
Malfunction decision
conditions If the compressor current exceeds the current limit value for
10 seconds, the LED will display the failure.
Supposed causes
●
Wiring mistake
●
Over load protector faulty
●
System block
●
Outdoor PCB faulty
Trouble shooting:
Current protection of compressor
Current protection of compressor
Judge 1: Check whether the input
current of the power supply wire
is more than 12.5A(18K) (For
27K, it is 17.For 30K, it is 18.5.For
36K, it is 23A)
Judge 1: Check whether the input
current of the power supply wire
is more than 12.5A(18K) (For
27K, it is 17.For 30K, it is 18.5.For
36K, it is 23A)
Yes
Replace the electric control box
Replace the electric control box
Check whether the
refrigerant system
is ok
Check whether the
refrigerant system
is ok
Judge 2: Check whether the
outdoor ambient temperature
is higher than 50
℃
Judge 2: Check whether the
outdoor ambient temperature
is higher than 50
℃
No
Stop the unit
Stop the unit Yes
Judge 3: Check whether the
outdoor unit is bad ventilation
Judge 3: Check whether the
outdoor unit is bad ventilation
No
Make the outdoor unit ventilate well
Make the outdoor unit ventilate well Yes
Judge 5: The refrigerant pipe is
blocked
Judge 5: The refrigerant pipe is
blocked
No
Let the refrigerant out, then use the high pressure
nitrogen or refrigerant to blow pipe, vacuumize
and charge the refrigerant again
Let the refrigerant out, then use the high pressure
nitrogen or refrigerant to blow pipe, vacuumize
and charge the refrigerant again
Yes
Judge 4: Check whether the
heat exchanger is dirty
Judge 4: Check whether the
heat exchanger is dirty
No
Clean the heat exchanger
Clean the heat exchanger Yes
Yes
Replace outdoor main
board,and check whether the
system can run normally
Replace outdoor main
board,and check whether the
system can run normally
No
Yes
Trouble is solved
Trouble is solved
Replace outdoor main board
Replace outdoor main board No