Thermistor Or Related Abnormality - Daikin Super Multi NX FFQ25B8V1B Service Manual

Troubleshooting for SA Indoor Unit - FFQ, FCQ, FDBQ, FBQ, FHQ Series
6.6

Thermistor or Related Abnormality

Remote The table below describes the 2 thermistor abnormalities.
Controller
Error
Display
C4
C9
Method of Malfunction detection is carried out by the temperature detected by thermistor.
Malfunction
Detection
Malfunction When during compressor operation:
Decision
or
Conditions
Supposed
Causes
Checking If the cause of the problem is related to the thermistors, the thermistors should be checked prior
to changing the indoor unit PCB.
thermistors
To check the thermistors, proceed as follows:
Refer to "Thermistor resistance check" on page 362 for detail.
326
Description
Defective indoor heat exchanger thermistor system
Defective room temperature thermistor system
Thermistor input > 4.96 V
Thermistor output < 0.04 V.
Disconnection of connector
Defective thermistor
Defective indoor unit PCB
Broken or disconnected wire
Step Action
1 Disconnect the thermistor from the indoor unit PCB.
2 Read the temperature and the resistor value.
Check if the measured values correspond with the values in the table of thermistor
3
resistance check.
SiBE121021_C
Service Diagnosis