Panasonic CS-E9SD3UAW Service Manual page 87

15.5.16 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 resistance 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
Caution
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 CH-HOT at
the start of heating
Outdoor PCB fault
87
4 WAYS VALVE
No
Good
OK
No
Good
No
OK
continuity
(open)
Remove CN-HOT.
Measure continuity
of the coil
OK
OK (Depending on 4-way valve model)
No supply
Replace Outdoor PCB
1
YELLOW
CN-HOT
YELLOW
(WHT)
2
COIL COMPLETE
Reconnect CN-HOT
(4-way valve connector)
Attach and screw the V-coil
to solenoid valve
V-coil fault
Replace
CN-HOT
(VH9-2)
V-coil only
1 2 3
Reverse solenoid valve faulty
Replace the 4-way valve
4 WAYS
VALVE