Panasonic CS-VZ9SKE Service Manual page 127

17.4.26 F90 (PFC Protection)
Troubleshooting
Is PFC protection activated occasionally, or is F90 stored in the memory only?
Diagnosis Procedures and Cause
PFC protection is activated at every operation
PFC protection
is activated
occasionally
127
Measures to be Taken
PFC protection is activated as a
protection against supply voltage drop
or instantaneous power interruption.
Replace the outdoor unit control board.