Thermistor Or Related Abnormality (Sa Indoor Unit) - Daikin 3MKS50E3V1B Service Manual

SiBE121135
6.6

Thermistor or Related Abnormality (SA Indoor Unit)

C4, C9
Remote
Controller
Display
Method of The temperatures detected by the thermistors determine thermistor errors.
Malfunction
Detection
Malfunction
The thermistor input is more than 4.96 V or less than 0.04 V during compressor operation.
Decision
Conditions
Supposed
Causes
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.325
C4 : Indoor heat exchanger thermistor (R2T, R3T)
C9 : Room temperature thermistor (R1T)
Service Diagnosis
Troubleshooting for SA Indoor Unit - FCQG, FFQ, FHQ, FDBQ, FBQ Series
Disconnection of connector
Defective thermistor
Defective indoor unit PCB
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.
Is it normal?
YES
Check No. 01
Check the thermistor resistance
value.
Is it normal?
YES
NO
NO
Correct the connection.
Replace the thermistor.
(Replace the indoor unit PCB.)
Replace the indoor unit PCB.
(R14406)
291