Panasonic WH-MXC09J3E8 Service Manual page 168

17.5.19 Tank Temperature Sensor Abnormality (H72)
Malfunction Decision Conditions:
When tank connection is set to ON, the temperatures detected by the tank temperature sensor are used to
determine sensor error.
Malfunction Caused:
1 Faulty connector connection.
2 Faulty sensor.
3 Faulty indoor unit PCB (main).
Abnormality Judgment:
Continue for 5 seconds.
Troubleshooting:
Is the abnormality happened during
tank connection set to ON?
Yes
Check the terminal board assembly no. 15 and
no.16, and CN-TH2 connector connections:
- Turn OFF the power
- Check the connector connections
Tank Sensor Characteristics
11
10
9
8
7
6
5
4
3
2
1
0
-10 0
Temperature (°C)
Caution
No
Check the tank temperature sensor:
- Plug out connector from the indoor unit PCB (main)
- Measure the resistance of the tank temperature
sensor
10 20 30 40 50
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
- Defect in indoor unit PCB (main)
- Replace the indoor unit PCB (main)
Is the terminal board assembly
no. 15 and no. 16, and CN-TH2
connector connections normal?
Yes
Is the measured resistance of the
tank temperature sensor matches
the value specified in its
characteristic chart?
Yes
168
No
- Connector poor contact
- Correct the connection
- Defect in tank temperature sensor
No
- Replace the tank temperature
sensor
- Defect in indoor unit PCB (main)
- Replace the indoor unit PCB (main)