Daikin REYQ-XA, Service Manual

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SiUS371901E Troubleshooting by Error Code
Service Diagnosis 278
3.22 Thermistor Abnormality
Error Code
C4, C5, C9, CA
Applicable
Models
C4, C5 : All indoor units
C9 : except FXTQ-TA and CXTQ-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 control PCB
„
Defective connector connection
„
Broken or disconnected wire
Troubleshooting
Notes:
∗
1. Error code and thermistor
∗
2. Refer to page 282 for C9 for FXTQ-TA and CXTQ-TA models
Refer to page 385.
Is the
thermistor normal?
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 control PCB. Then,
insert the connector again.
Remove the thermistor from
the indoor unit control PCB,
and then make resistance
measurement of the thermistor
using a multimeter.
Normal?
Normal (The error is caused by
defective contact.)
YES
NO
Replace the indoor unit
control PCB (A1P).
YES
Replace the thermistor (
∗
1).
NO
CHECK 11
Error Code Thermistor
Except
FXMQ-PB and
FXTQ-TA,
CXTQ-TA
FXMQ-PB
FXTQ-TA,
CXTQ-TA
C4
Indoor heat exchanger liquid pipe thermistor R2T R2T R2T
C5
Indoor heat exchanger gas pipe thermistor R3T R3T R3T
C9
Suction air thermistor R1T R1T
∗
2
CA Discharge air thermistor — R4T —
CHECK 11