Panasonic CS-VZ9SKE Service Manual page 121

17.4.20 H98 (Indoor Unit Overpressure Protection)
Troubleshooting
Check for clogged filter on the indoor unit.
Check for bad connection of the connector of indoor unit heat
exchanger temperature sensor.
Check for the characteristics of the indoor unit heat exchanger
temperature sensor.
Refer to the characteristic table for electronic circuit diagram.
(Remove the connector and check the resistance value of the sensor.)
For some models, the sensor is not connected by a connector but it is directly soldered to the board.
In this case, replace the control board.
Diagnosis Procedures and Cause
No abnormality is observed
No abnormality is observed
No abnormality is observed
An abnormality is observed
Disconnection/Imperfect
connection of the connector
An abnormality is observed
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Measures to be Taken
Clean the filter.
Fix the problem.
Replace the indoor unit heat
exchanger temperature sensor.
Replace the indoor unit control board.