Daikin FTKM18PVMK, Service Manual

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Troubleshooting SiMT041509E
77 Service Diagnosis
4.19 Thermistor or Related Abnormality (Outdoor Unit)
Error Code
H9
,
J3
,
J6
,
P4
Method of Error
Detection This fault is identified based on the thermistor input voltage to the microcomputer.
A thermistor fault is identified based on the temperature sensed by each thermistor.
Error Decision
Conditions
„
The voltage between the both ends of the thermistor is above 4.96 V or below 0.04 V with
the power on.
„ J3
error is judged if the discharge pipe temperature is lower than the heat exchanger
temperature.
Supposed
Causes
„
Disconnection of the connector for the thermistor
„
Thermistor corresponding to the error code is defective.
„
Defective heat exchanger thermistor in the case of
J3
error (outdoor heat exchanger
thermistor in cooling operation, or indoor heat exchanger thermistor in heating operation)
„
Defective outdoor unit PCB
Troubleshooting In case of
P4
Replace the outdoor unit PCB (main PCB).
P4
: Radiation fin thermistor
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.