Daikin SkyAir FHQ24PVJU - Thermistor Abnormality

SiUS281811EA Troubleshooting by Error Codes
Part 6 Service Diagnosis 241
Note(s)
Reference
4.21 Thermistor Abnormality
Error Code C4, C5, C9, CA
Applicable
Models
C4, C5: All indoor units
C9: except FTQ-TA models
CA: FBQ-P models only
Method of Error
Detection
The error is determined by the temperature detected by the thermistor.
Error Decision
Conditions
The thermistor becomes disconnected or shorted while the unit is running.
Supposed
Causes
 Defective thermistor
 Defective indoor unit PCB
 Defective connector connection
 Broken or disconnected wire
Troubleshooting
∗1. Error code and thermistor
∗2. Refer to page 245 for C9 for FTQ-TA models.
CHECK 11 Refer to page 301.
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
Remove the thermistor from
the indoor unit PCB. Then,
insert the connector again.
Remove the thermistor from
the indoor unit PCB, and then
make resistance measurement
of the thermistor using a
multimeter.
CHECK 11
Normal (The error is caused by
defective contact.)
YES
NO
Replace the indoor unit main
PCB (A1P).
YES
Replace the thermistor (1).
NO
Is the thermistor
normal?
Normal?
Error Code Thermistor
FCQ-TA
FHQ-P
FHQ-M
FAQ-TA
FBQ-P FTQ-TA
C4 Heat exchanger liquid pipe thermistor R2T R2T R2T
C5 Heat exchanger gas pipe thermistor R3T R3T R3T
C9 Suction air thermistor R1T R1T ∗2
CA Discharge air thermistor — R4T —