Thermistor Or Related Abnormality - Daikin MKS-T Series Service Manual

Troubleshooting for MSP Duct Type Indoor Unit
6.6

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 voltage between the both ends of the thermistor is either 4.96 V or more, or 0.04 V or less
Conditions with the power on.
Supposed
 Disconnection of connector
Causes  Defective thermistor(s)
 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.
To check the thermistors, proceed as follows:
1. Disconnect the thermistor from the indoor unit PCB.
2. Read the temperature and the resistance value.
3. Check if the measured values correspond with the values in the table of thermistor
Check the connection of
connectors.
C4: Indoor heat exchanger thermistor 1 (liquid pipe) (R2T)
C5: Indoor heat exchanger thermistor 2 (R3T)
C9: Room temperature thermistor (R1T)
Reference
Check No.01 Refer to P.169
133
resistance check.
Be sure to turn off the power switch before connecting or disconnecting
Caution connectors, or parts may be damaged.
Normal?
YES
Check No. 01
Check the thermistor resistance
value.
Normal?
YES
NO
NO
SiSG121917E
Correct the connection.
Replace the defective
thermistor.
Replace the indoor unit PCB
(control PCB).
(R21870)
Part 6 Service Diagnosis