Panasonic CU-4Z80TBE Service Manual page 294

16.2.5 H27 (Outdoor Air Temperature Sensor Abnormality)
Malfunction Decision Conditions

During startup and operation of cooling and heating, the temperatures detected by the outdoor air temperature
sensor are used to determine sensor errors.
Malfunction Caused

Faulty connector connection.

Faulty sensor.

Faulty PCB.
Troubleshooting
When abnormality indication starts again
Check the connector connection:
● Turn off the power
● Check the connector connection
Is the connector connection normal?
Check the outdoor air temperature sensor:
● Plug out connector from the outdoor unit PCB
● Measure the resistance of the outdoor air temperature
sensor
Is the measured resistance of the outdoor air temperature
sensor matches the value specified in its characteristic
chart?
Sensor (Thermistor)
Characteristics
70
Outdoor Air Sensor
1
Outdoor Heat
2
60
Exchanger Sensor
50
40
1
30
2
20
10
0
-10 0 10
Temperature (°C)
YES
YES
20 30 40 50
For safety reason and to prevent component
breakdown, always switch off the power
Caution
before remove and connect the component.
NO
● Connector poor contact
● Correct the connection
NO ● Defect in outdoor air temperature sensor
● Replace the outdoor air temperature sensor
● Defect in outdoor unit PCB
● Replace the outdoor unit PCB
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