Thermistor Or Related Abnormality (Outdoor Unit) - Daikin FTX-N Series Service Manual

SiUS041638EA

4.22 Thermistor or Related Abnormality (Outdoor Unit)

H9, J3, J6, P4
Error Code
Method of Error
This fault is identified based on the thermistor input voltage to the microcomputer.
Detection
A thermistor fault is identified based on the temperature sensed by each thermistor.
Error Decision
 The voltage between the both ends of the thermistor is either 4.96 V or more, or 0.04 V or less
Conditions
 J3 error is judged if the discharge pipe temperature is lower than the heat exchanger
Supposed
 Disconnection of the connector for the thermistor
Causes  Defective thermistor(s)
 Defective heat exchanger thermistor in the case of J3 error (outdoor heat exchanger thermistor
 Defective outdoor unit PCB
Troubleshooting
In case of P4
Replace the outdoor unit PCB (main PCB).
P4 : Radiation fin thermistor
Service Diagnosis
with the power on.
temperature.
in cooling operation, or indoor heat exchanger thermistor in heating operation)
Be sure to turn off the power switch before connecting or disconnecting
Caution connectors, or parts may be damaged.
Troubleshooting
88