Panasonic WH-UD05JE5 Service Manual page 212

19.5.23 Tank Booster Heater OLP Abnormality (H91)
Malfunction Decision Conditions:
During operation of tank booster heater, and tank booster heater OLP open circuit.
Malfunction Caused:
1 Faulty connector connection.
2 Faulty tank booster heater overload protector (OLP).
3 Faulty indoor unit PCB (main).
Abnormality Judgment:
Continue for 60 seconds.
Troubleshooting:
Is the abnormality happened during
operation of tank booster heater?
Check the CN-OLP2 connector connection:
- Turn OFF the power.
- Check the connector connection.
Is the CN-OLP1 connector
connection normal?
Check tank booster heater OLP continuity:
- Turn OFF power supply.
- Reset tank booster heater OLP.
- Measure the continuity of OLP.
Is there any continuity?
Caution
Yes
No
Yes
No
- Defect in tank booster heater OLP.
- Replace tank booster heater OLP.
Yes
- Defect in indoor unit PCB (main).
- Replace the indoor unit PCB (main).
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).
- Connector poor contact.
- Correct the connection.
212
Use a test pen to push
this button to reset OLP
Multimeter to
measure continuity