Daikin REYQ-TA Series, Service Manual

Page: 209 / 324

SiUS371614E Troubleshooting by Error Code
Service Diagnosis 196
3.18 Thermistor Abnormality
Error Code
C4, C5, C9, CA
Applicable
Models
C4, C5 : All indoor units
C9 : except FXTQ-TA models
CA : FXMQ-PB models only
Method of Error
Detection
The error is detected by temperature detected by 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
Note:
∗
1. Error code and thermistor
∗
2. Refer to page 200 for C9 for FXTQ-TA models
Refer to page 282.
Is the
thermistor normal?
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
5 k
Ω
to 90 k
Ω
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.
Normal (The error is caused by
defective contact.)
YES
NO
Replace the indoor unit main
PCB (A1P).
YES
Replace the thermistor (
∗
1).
NO
CHECK 11
Error Code Thermistor
Except
FXMQ-PB and
FXTQ-TA
FXMQ-PB FXTQ-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 —
CHECK 11