Thermistor Abnormality - Daikin VRV IV-S RXTQ-TAVJU Series Service Manual

SiUS331604E

4.13 Thermistor Abnormality

C4, C5, C9, CA
Error Code
Applicable
C4, C5, C9: All indoor units
CA: FXMQ-PB models only
Models
Method of Error The error is determined by the temperature detected by the thermistor.
Detection
Error Decision The thermistor becomes disconnected or shorted while the unit is running.
Conditions
Supposed
Causes
Troubleshooting
Note: Error code and thermistor
CHECK 11
Service Diagnosis
Defective thermistor
Defective indoor unit PCB
Disconnection of connector
Be sure to turn off the power switch before connecting or disconnecting
Caution
connectors, or parts may be damaged.
Remove the thermistor from
the indoor unit PCB. Then,
insert the connector again.
Is the thermistor
normal?
NO
Remove the thermistor from
the indoor unit PCB, and then
make resistance measurement
of the thermistor using a
multimeter.
CHECK 11
5 to 90 kΩ
YES
Error Code
C4
Heat exchanger liquid pipe thermistor
C5 Heat exchanger gas pipe thermistor
C9 Suction air thermistor
CA Discharge air thermistor
Refer to page 231.
YES
NO
Thermistor
Troubleshooting by Error Code
Normal (The error is caused by
defective contact.)
Replace the thermistor.
Replace the indoor unit main
PCB (A1P).
Except FXTQ FXTQ
R2T R1T
R3T R2T
R1T —
R4T —
156