Panasonic CS-YE18NKV-6 Service Manual page 65

15.5.16 F90 (Power Factor Correction Protection)
Malfunction Decision Conditions

During startup and operation of cooling and heating, when Power Factor Correction (PFC) protection circuitry at
the outdoor unit main PCB senses abnormal high DC voltage level.
Malfunction Caused

DC voltage peak due to power supply surge.

DC voltage peak due to compressor windings not uniform.

Faulty outdoor PCB.
Troubleshooting
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