Midea M2OC-18HFN1-M Service Manual page 80

9.4.2.10 P2(Low pressure protection) error diagnosis and solution. (Only for M4OC-36HRFN1-M)
Error Code
Malfunction decision
conditions
Supposed causes
Trouble shooting:
P2
If the sampling voltage is not 5V, the LED will display the
failure.
● Wiring mistake
● Over load protector faulty
● System block
● Outdoor PCB faulty
Low pressure protection
Judge 1: Whether the
wiring between the low
pressure protector and main No
control board is connected
well or correctly
Yes
Judge 2: Whether
the low pressure
protector is broken
Method: Short connect the
low pressure protector
Yes
socket, check whether the
system can run normally, or
test the resistance.
No
Check whether
the refrigerant
system is ok
Judge 3: Check whether the
outdoor ambient
Yes
temperature is too low
No
Judge 4: The
refrigerant of the
system is leakage
Method: Connect the pressure
gauge to the gauge joint of the
system, check whether the Yes
pressure is lower than
0.14MPa
No
Judge 5: The refrigerant
Yes
pipe is blocked
No
Replace outdoor main board
Connect it well
Replace low pressure protector
Stop the unit
Leak hunting: Charge nitrogen or refrigerant
to the system, if the leakage is serious, there
will be distinct gas leakage "cici" sound; if the
leakage is slight, use the suds (mixture of
water and abluent is also ok if it can make
bubble) or electronic leak detector.
Let the refrigerant out, then use the high
pressure nitrogen or refrigerant to blow pipe,
vacuumize and charge the refrigerant again