Midea M2OC-18HFN1-M Service Manual page 82

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