Troubleshooting for Indoor Unit
5.4
Thermistor or Related Abnormality (Indoor Unit)
C4, C9
Remote
Controller
Display
Method of
The temperatures detected by the thermistors are used to 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
Disconnection of connector
Supposed
Defective thermistor
Causes
Defective indoor unit PCB
Troubleshooting
Check No.01
Refer to P.191
Check the connection of
connectors.
C4 : Indoor heat exchanger thermistor
C9 : Room temperature thermistor
153
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
SiUS12-928_B
Correct the connection.
Replace the thermistor.
(Replace the indoor unit PCB.)
Replace the indoor unit PCB.
(R15717)
Service Diagnosis