Panasonic WH-UD05JE5 Service Manual page 214

19.5.25 Outdoor High Pressure Protection (H98)
Malfunction Decision Conditions:
During operation of heating, when pressure 4.0 MPa and above is detected by outdoor high pressure sensor.
Malfunction Caused:
1 Faulty water pump.
2 Insufficient water flow rate in system.
3 Water leak in system.
4 2/3 way closed.
5 Clogged expansion valve or strainer.
6 Excessive refrigerant.
7 Faulty outdoor high pressure sensor.
8 Faulty outdoor unit PCB (main).
Troubleshooting:
Check the system water pump.
Is the water pump working?
Yes
Check the system water
flow rate.
Is the water pump speed
adjusted according to system
hydraulic external static pressure?
Yes
Check the system water passage.
Is there any water leakage?
No
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Caution
No
Replace the faulty water
pump.
No
Readjust the water
pump speed.
Yes
Fix the system water
leakage.
Check the 2/3 way valve.
Is the 2/3 way valve closed?
No
Check for clogged expansion
valve or strainer.
Is the expansion valve or
strainer clogged (ice formed)?
No
Check refrigerant amount.
Is the additional refrigerant
amount filled correctly?
Yes Yes
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Yes
Open the 2/3 way valve.
- Replace the expansion
Yes
valve and/or strainer.
- Reclaim and recharge
refrigerant.
Reclaim and recharge with
No
correct amount of
refrigerant.
- Replace the outdoor unit
PCB (main).
- Replace the outdoor high
pressure sensor.