Daikin FTXN50L - EA: 4 Way Valve Abnormality

Service Diagnosis
47
EA
Description
4 WAY VALVE ABNORMALITY
Possible Root
cause
1. Thermistor defective.
2. 4 way valve defective.
3. Outdoor PCB defective.
4. Insufcientgas.
5. Foreign substance mixed in refrigerant.
6. Stop valve defective.
7. Disconnect of 4 way valve coil.
Troubleshooting
Harness
disconnected?
Check the four way
valve switching
output.
Yes
No
Check the continuity of the four
way valve coil and harness.
Disconnect the harness from
the connector.
Functioning
Correct the four way valve
coil.
Replace the four way valve
coil.
Replace the defective
thermistor(s).
Malfunction
Replace the outdoor unit PCB.
Reconnect the thermistor(s).
Reconnect the harness.
Resistance
between harnesses.
No
Yes
Any thermistor
disconnected?
Yes
No
Check the thermistors.
Malfunction
Functioning
Refer to the refrigerant
line check procedure.
Replace the four way valve
(defective or dust-clogged).
Check the
refrigerant
line.
Malfunction
Functioning
Four way valve
coil disconnected
(loose)?
No
Yes
within spec?
*Remark:
Refer to Appendix A for thermistor resistance checking procedures.(Page 72, item 6.1)
Refer to Appendix A for Four way valve performance checking procedures.(Page 74 ,item 6.2)
Refer to Appendix A for Inverter unit refrigerant check procedures.(Page 75 ,item 6.4)