F11 (4-Way Valve Switching Failure) - Panasonic CS-RZ25VKRW Service Manual

18.4.19 F11 (4-way Valve Switching Failure)

Malfunction Decision Conditions

When indoor heat exchanger is cold during heating (except deice) or when indoor heat exchanger is hot during
cooling and compressor operating, the 4-way valve is detected as malfunction.
Malfunction Caused

Indoor heat exchanger (pipe) thermistor

4-way valve malfunction
Troubleshooting
When abnormality starts again.
Check the indoor pipe temperature
thermistor:
● Plug out connector (CN-TH) from the
indoor unit PCB.
● Measure the resisitance of the indoor
heat exchanger temperature thermistor.
Is the measured resistance of the indoor pipe
temperature thermistor matches the value
specified in its characteristic chart?
YES
Problem occurs in heating mode only?
NO, it happen in cooling/dry as well.
Is 4-way solenoid valve being energised?
NO
The 4-way valve may have been damaged or
wrongly connected between discharge and
suction tube.
● Check connecting tubes to 4-way valve.
* Check gas side pipe – for hot gas flow in cooling mode
For safety reason and to prevent component
breakdown, always switch off the power before
remove and connect the component.
● Defect in indoor pipe temperature
NO
thermistor.
● Replace the indoor pipe temperature
thermistor.
YES
YES
4-way valve not working
Outdoor PCB fault
(not energize).
● Replace
Outdoor PCB.
Check CN-HOT
connection
(4-way valve connector).
Check V-coil attach to
solenoid valve.
Check valve v-coil
continuity.
Measure voltage
supplied to CN-HOT at
the start of heating.
Outdoor PCB fault
● Replace Outdoor PCB.
142
4 WAYS VALVE
YELLOW
YELLOW
COIL COMPLETE
No
Good.
● Reconnect CN-HOT
(4-way valve connector).
OK
No
Good.
● Attach and screw the V-coil
to solenoid valve.
No
OK
continuity
(open).
V-coil fault
● Replace
V-coil only.
Remove CN-HOT.
Measure continuity
of the coil.
OK
OK (Depending on 4-way valve model).
Reverse solenoid value faulty
● Replace the 4-way valve.
No supply.
1
CN-HOT
(WHT)
2
4 WAYS
VALVE
CN-HOT
(VH3-2)
1 2 3