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

Troubleshooting

4.19 Thermistor or Related Abnormality (Outdoor Unit)

H9, J3, J6 and P4
Error Code
Description

Thermistor or Related Abnormality (Outdoor Unit)

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.
 The voltage between both ends of the thermistor is either 4.96 V or more, or 0.04 V or less
Error Decision
Conditions
 J3 error is judged if the discharge pipe temperature is lower than the heat exchanger
 Disconnection of the connector for the thermistor
Supposed
 Defective thermistor(s)
Causes
 Defective outdoor heat exchanger thermistor in the case of J3 error
 Defective outdoor unit PCB
In case of P4 (Radiation fin thermistor)
Troubleshooting
Be sure to turn off the power switch before connecting or disconnecting connectors, or parts
may be damaged.
Caution
Replace the outdoor unit PCB (main PCB)
In case of H9, J3, J6 and P4
Troubleshooting
Be sure to turn off the power switch before connecting or disconnecting connectors, or parts
may be damaged.
Caution
H9 : Outdoor temperature thermistor
76
with the power on.
temperature.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
Caution
Turn on the power again.
Error displayed
again on remote
controller?
Yes
Check the thermistor resistance value.
Normal?
J3 error: the discharge
pipe temperature is
lower than the heat
exchanger temperature.
Cooling : Outdoor heat
exchanger
temperature.
Heating : Indoor heat
exchanger
temperature.
Yes
Check the indoor heat exchanger
thermistor resistance value in the
heating operation.
Indoor heat
exchanger thermistor
functioning?
Yes
No
Reconnect the connectors
No
Replace the defective
thermistor(s) of the following
thermistors.
• Outdoor temperature
thermistors.
• Discharge pipe thermistor.
• Outdoor heat exchanger
thermistor.
No
Replace the indoor heat
exchanger thermistor.
Replace the outdoor unit PCB.
DAMA-SM-21-003
or thermistors
Service Diagnosis