Panasonic CU-3E19RBU-5 Service Manual page 85

15.2.20 F96 (Power Transistor Module Overheating Protection)
Malfunction Decision Conditions

Compressor Overheating: During operation of cooling and heating, when the compressor OL is activated.

Heat Sink Overheating: During operation of cooling and heating, when heat sink temperature data (90°C (194°F))
is detected by the heat sink temperature sensor.
Malfunction Caused

Compressor OL connector poor contact.

Compressor OL faulty.

IPM overheat due to short circuit of hot discharge air flow.

IPM overheat due to defective of outdoor fan motor.

IPM overheat due to defective of internal circuitry of IPM.

IPM overheat due to defective IPM temperature sensor.
Abnormality Judgment:

4 times happen within 30 minutes.
Troubleshooting
installation condition (during
cooling or softdry operation)
Is the compressor OL connector
For safety reason and to prevent component
breakdown, always switch off the power before
Caution
remove and connect the component.
Check the outdoor unit
Is there any improper
heat radiation?
No
Is outdoor fan motor
operating?
Yes
connection normal?
Yes
Yes
- Reinstall the outdoor unit
- Remove the obstacle(s)
- Clean the outdoor heat exchanger
No
Replace the outdoor fan
motor.
No
- Connector poor contact
- Correct the connection
- Defect in IPM
- Replace the outdoor unit PCB
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