158
17.5.15 Deice Circulation Error (H65)
Malfunction Decision Conditions:
During startup and operation of deice (mode 2), the water flow (> 5l/min) detected by the water flow switch is
used to determine deice circulation error.
Malfunction Caused:
1 Water flow in air-to-water heatpump indoor unit circuitry.
2 Faulty indoor unit water flow switch.
3 Faulty indoor unit water pump.
4 Faulty indoor unit PCB.
Abnormality Judgment:
Continue for 10 seconds.
Troubleshooting:
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Use buffer tank to
separate external water
pump from air-to-water
heatpump indoor unit
circuit.
During deice (mode 2), check if indoor
unit water pump operates.
Is there any continuity?
No
- Defect in indoor unit PCB
- Replace the indoor unit PCB
Stop operation and turn OFF power.
Plug out the connector of water flow
switch (CN-FLOW) in the indoor unit
PCB and measure its continuity.
Check if external water pump is
used and it is directly installed to
the air-to-water heatpump
indoor unit circuit. (without buffer
tank)
Turn OFF the power.
Disconnect indoor unit water
pump connector CN-PUMP2.
Operate the air-to-water
heatpump unit. During deice
(mode 2), check if the indoor
unit water pump duty
command signal generated?
No
No
- Defect in indoor unit PCB
- Replace the indoor unit PCB
Yes
Yes
Yes
- Defect in indoor unit water
flow switch
- Replace the indoor unit
water flow switch
No
- Defect in indoor unit water
pump
- Replace the indoor unit
water pump
Yes
External
Pump
Panasonic
Air-to-Water
Heatpump
Indoor Unit
CAUTION
● When external pump is used, be sure to install
it in independent water circuit and not direct to
the air-to-water heatpump indoor unit circuit.
Caution
