Daikin REYQ-AATJA, Service Manual

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Troubleshooting by Error Code SiUS372201EA
329 Part 6 Service Diagnosis
Note(s)
Reference
3.24 Thermistor Abnormality
Applicable
Models
C4, C5 : All indoor units
C9 : except FXTQ-TA and CXTQ-TA models
CA : FXMQ-PB models only
Error Code
C4, C5, C9, CA
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 control PCB
 Defective connector connection
 Broken or disconnected wire
Troubleshooting

1. Error code and thermistor

2. Refer to page 333 for C9 for FXTQ-TA and CXTQ-TA models.
CHECK 11 Refer to page 434.
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 measure the
resistance 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
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 —