Panasonic CS-MZ20UD3EA Service Manual ▷ View online
89
16.4.21 F90 (Power Factor Correction Protection)
Malfunction Decision Conditions
To maintain DC voltage level supply to power transistor.
To detect high DC voltage level after rectification.
Malfunction Caused
During startup and operation of cooling and heating, when Power Factor Correction (PFC) protection circuitry at
the outdoor unit main PCB senses abnormal DC voltage level for power transistors.
When DC voltage detected is LOW, transistor switching will turn ON by controller to push-up the DC level.
When DC voltage detected is HIGH (391Vdc – 425Vdc), active LOW signal will send by the controller to turn OFF
relay RY-C.
Troubleshooting
90
16.4.22 F91 (Refrigeration Cycle Abnormality)
Malfunction Decision Conditions
The input current is low while the compressor is running at higher than the setting frequency.
Malfunction Caused
Lack of gas.
3-way valve close.
Troubleshooting
91
16.4.23 F93 (Compressor Rotation Failure)
Malfunction Decision Conditions
A compressor rotation failure is detected by checking the compressor running condition through the position
detection circuit.
Malfunction Caused
Compressor terminal disconnect
Faulty Outdoor PCB
Faulty
compressor
Troubleshooting
92
16.4.24 F95 (Outdoor High Pressure Protection: Cooling or Soft Dry)
Malfunction Decision Conditions
During operation of cooling or soft dry, when outdoor unit heat exchanger high temperature data is detected by
the outdoor unit heat exchanger thermistor.
Malfunction Caused
Outdoor heat exchanger temperature rise due to short-circuit of hot discharge air flow.
Outdoor heat exchanger temperature rise due to defective of outdoor fan motor.
Outdoor heat exchange temperature rise due to defective outdoor heat exchanger thermistor.
Outdoor heat exchanger temperature rise due to defective of outdoor unit PCB.
Troubleshooting
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