Lennox MPA009S4S Service Manual page 136

Error Code:
F0
Description: Outdoor compressor current overload sensed
General Note: If the outdoor current exceeds the current limit value, the LED will display the failure.
Check whether the input current of the power
supply should not exceed more than 12A for 18K BTU
Check whether the refrigerant system is OK.
Check whether the outdoor ambient temperature
is higher than 50°C or 122 F
Check if outdoor unit has proper ventilation.
Check outdoor coils. Outdoor coils should be clean
Judge 5: The refrigerant pipe is blocked.
Replace outdoor main board, and check whether the
system can run normally.
Replace the electric control box.
units.
For 30K, 18.5A.
For 36K, it is 23A
Yes
No
No
and free of any debris.
No
No
No
No
Replace outdoor main board.
Yes
Stop the unit.
Yes
Correct poor ventilation to outdoor unit.
Yes
Clean outdoor coils.
Recover refrigerant and remove restriction(s).
Yes
Perform proper vacuum procedures, then
restart system.
Yes
Yes
Problem Solved.
136