Panasonic CU-3E19RBU-5 Service Manual page 75

15.2.10 H37 (Outdoor Liquid Pipe Temperature Sensor Abnormality)
Malfunction Decision Conditions

During startup and operation of cooling and heating, the temperatures detected by the outdoor liquid pipe
temperature sensor are used to determine sensor errors.
Malfunction Caused

Faulty connector connection.

Faulty sensor.

Faulty PCB.
Abnormality Judgment:

Continue for 5 seconds.
Troubleshooting
Sensor (Thermistor)
Characteristics
70
1
Outdoor Air Sensor
2
Outdoor Heat Exchanger
60
Sensor
50
40
1
30
2
20
10
0
-10 0 10 20 30
(14) (32) (50) (68) (86)
Temperature °C (°F)
Caution
Check the connector connection:
- Turn off the power
- Check the connector connection
Is the connector
connection normal?
Check the outdoor liquid pipe temperature sensor:
- Plug out connector from the outdoor unit PCB
- Measure the resistance of the outdoor liquid pipe
temperature sensor
Is the measured resistance of the
outdoor liquid pipe temperature
sensor matches the value
specified in its characteristic chart?
40 50
(104) (122)
For safety reason and to prevent component
breakdown, always switch off the power before
remove and connect the component.
No
Yes
No
Yes
75
- Connector poor contact
- Correct the connection
- Defect in outdoor liquid pipe
temperature sensor
- Replace the outdoor liquid
pipe temperature sensor
- Defect in outdoor unit PCB
- Replace the outdoor unit PCB