Panasonic WH-ADC0309H3E Service Manual page 185

17.5.36 Four Way Valve Abnormality (F25)
Malfunction Decision Conditions:
1 During heating operation, when the indoor pipe temperature of thermostat ON indoor unit < 0°C.
2 During cooling operation, when the indoor pipe temperature of thermostat ON indoor unit > 45°C.
Malfunction Caused:
1 Faulty sensor.
2 Faulty connector connection.
3 Faulty outdoor unit PCB (noise filter/main).
4 Faulty four way valve.
Abnormality Judgment:
Continue 4 times in 30 minutes.
Troubleshooting:
Check the indoor pipe
temperature sensor.
Does it conform to the
sensor characteristic chart?
Yes
Is F25 occur during heating
operation?
No
Is the four way valve coil energize
during cooling operation?
No
No
Replace the indoor pipe
temperature sensor.
Yes
Yes
Replace the outdoor unit
PCB (noise filter/main).
Replace the four way valve.
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Four way valve coil
disconnected (loose)?
No
Is the harness out of the
CN-HOT connector?
No
Check the continuity of the
four way valve coil.
Disconnect the harness from the
CN-HOT connector. Resistance
between harness about 1.52 kohm?
Yes
Measure AC voltage supply to
CN-HOT (pin 1 & 3) during heating
operation.
Is the voltage supply to four
way valve 230 Vac?
Yes
185
Yes
Connect the four way valve
coil.
Yes
Reconnect the harness.
No
Replace the four way valve
coil.
4 WAYS
CN-HOT VALVE
(VH3-2)
1 2 3
No
Replace the outdoor unit
PCB (noise filter/main).
Replace the four way valve.