Thermistor Or Related Abnormality - Daikin FDMQ-R Series Manual

Troubleshooting
4.7

Thermistor or Related Abnormality

C4, C5, C9
Error Code
Method of Error
The temperatures detected by the thermistors determine thermistor errors.
Detection
Error Decision
The thermistor is disconnected or shorted while the unit is running.
Conditions
Supposed
 Disconnection of connector
Causes
 Defective thermistor(s)
 Breaking of wires
 Defective indoor unit PCB
Troubleshooting
If the cause of the problem is related to the thermistors, the thermistors should be checked prior to
changing the indoor unit PCB.
Check No.01
To check the thermistors, proceed as follows:
Refer to P.105
C4 : Indoor heat exchanger thermistor 1 (liquid pipe) (R2T)
C5 : Indoor heat exchanger thermistor 2 (R3T)
C9 : Room temperature thermistor (R1T)
Note:
When replacing the defective thermistor(s), replace the thermistors as ASSY.
71
Step Action
1 Disconnect the thermistor from the indoor unit PCB.
2 Read the temperature and the resistance value.
Check if the measured values correspond with the values in the table of thermistor
3
resistance check.
Be sure to turn off the power switch before connecting or disconnecting
Caution
connectors, or parts may be damaged.
Check the connection of
connectors.
Normal?
YES
Check No. 01
Check the thermistor resistance
value.
Normal?
YES
NO
NO
SiUS071735EB
Correct the connection.
Replace the defective
thermistor(s).
Replace the indoor unit PCB
(control PCB).
(R24056)
Service Diagnosis