Panasonic CS-ME5RKUA Service Manual page 45

12.4.9 H28 (Outdoor Pipe Temperature Sensor Abnormality)
Malfunction Decision Conditions

During startup and operation of cooling and heating, the temperatures detected by the outdoor pipe 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 heat exchanger temperature sensor:
Plug out connector from the outdoor unit PCB.
Measure the resistance of the outdoor heat exchanger
temperature sensor.
Is the measured resistance of the outdoor heat exchanger
temperature sensor matches the value specified in its
characteristic chart?
Sensor (Thermistor)
Characteristics
70
60
50
40

30

20
10
0
14 32
YES
YES

Outdoor Air Sensor
 Outdoor Heat Exchanger
Sensor
50 68 86 104 122
Temperature (°F)
For safety reason and to prevent
component breakdown, always switch
off the power before remove and
connect the component.
No
Connector poor contact.
Correct the connection.
Defect in outdoor heat exchanger
No
temperature sensor.
Replace the outdoor heat exchanger
temperature sensor.
Defect in outdoor unit PCB.
Replace the outdoor unit PCB.
45