Panasonic WH-MXC09J3E8 Service Manual page 191

17.5.41 Power Factor Correction (PFC) Abnormality (F41)
Malfunction Decision Conditions:
During operation of cooling and heating, when the PFC protection circuitry in the outdoor unit PCB (main) senses
abnormal high DC voltage level.
Malfunction Caused:
1 Power supply surge.
2 Compressor windings not uniform.
3 Faulty outdoor unit PCB (main).
Abnormality Judgment:
Continue 4 times in 10 minutes.
Troubleshooting:
Check the supply voltage.
Supply voltage as specified?
Yes
Operate the system. Verify PFC
abnormality by measuring the DC
voltage between DCP-OUT and DCN-
OUT of the outdoor unit PCB (main).
Is the DC voltage between DCP-
OUT and DCN-OUT normal
(between 285-315 Vdc)?
No
For safety reason and to prevent component breakdown,
Caution always switch off the power before remove and connect the component.
No
Correct the power supply.
- Defect in PFC circuitry
Yes
- Replace the outdoor unit
PCB (main)
Check the compressor winding resistance:
- Turn OFF the power supply and disconnect
the harnesses U, V, and W
- Measure the winding resistance between U-V,
V-W, and W-U
Are the compressor's winding
resistance (U-V, V-W, U-W)
191
uniform?
No
Replace the compressor.
Yes
Replace the outdoor unit
PCB (main).