164
17.5.15 Deice Circulation Error (H65)
Malfunction Decision Conditions:
During startup and operation of deice (mode 2), the water flow (> 10l/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 internal 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-PUMP1. Operate the
auto-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
- 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.
