Daikin FTXN25L Service Manual page 68

Description INSUFFICIENT GAS
Possible Root 1. Disconnection of the discharge pipe thermistor, indoor or outdoor heat exchanger,room or
cause outdoor temperature thermistor.
2. Closed stop valve.
3. Refrigerant shortage (refrigerant leakage).
4. Poor compression performance of compressor.
5. Defective electronic expansion valve.
Troubleshooting
*Remark:
Refer to Appendix A for thermistor resistance checking procedures.(Page 72, item 6.1)
Refer to Appendix A for electronic expansion device checking procedures.(Page 74, item 6.2)
Check stop valve.
Stop valve closed?
No
Check indoor and outdoor
coil thermistor.
Thermistor in
actual position?
Yes
Check the indoor coil,
outdoor coil and discharge
pipe thermistor resistance.
Resistance
normal?
Yes
Check EXV.
EXV functioning?
Yes
Check refrigerant charge
level.
Refrigerant
charge
sufficient?
Yes
Change outdoor PCB.
U0
Yes
Fully open stop valve.
No
Put the thermistor back
to actual position.
No
Change thermistor.
No
Change EXV.
No
Check for leakage.
Any leakage?
No
Add in refrigerant charge.
Service Diagnosis
Yes
Repair the leak point.
60