Troubleshooting for CTXS, FTXS, CDXS, FDXS, FVXS Series SiUS121502E118 Service Diagnosis5.2 Freeze-up Protection Control / Heating Peak-cut ControlError Code A5Method of ErrorDetection Freeze-up protection controlDuring cooling operation, the freeze-up protection control (operation halt) is activated accordingto the temperature detected by the indoor heat exchanger thermistor. Heating peak-cut controlDuring heating operation, the temperature detected by the indoor heat exchanger thermistor isused for the heating peak-cut control (operation halt, outdoor fan stop, etc.)Error DecisionConditions Freeze-up protection controlDuring cooling operation, the indoor heat exchanger temperature is below 0°C (32°F). Heating peak-cut controlDuring heating operation, the indoor heat exchanger temperature is above 65°C (149°F).SupposedCauses Short-circuited air Clogged air filter of the indoor unit Dust accumulation on the indoor heat exchanger Defective indoor heat exchanger thermistor Defective indoor unit PCBTroubleshootingCheck No.01Refer to P.166NONONOCheck No. 01Check the indoor heat exchangerthermistor.YESYES(R21064)YESYESNOCautionProvide sufficient air passage.Clean the air filter.Clean the indoor heatexchanger.Replace the indoor unit PCB(control PCB).Replace the indoor heatexchanger thermistor.Asdescribed in thethermistor characteristicchart?Check the air filter.Check the dust accumulation onthe indoor heat exchanger.Is there any short circuit?Dirty?Dirty?Check the air passage.Be sure to turn off the power switch before connecting or disconnectingconnectors, or parts may be damaged.
