Daikin VRV Aurora RXLQ-TATJU Series, Service Manual

Page: 277 / 442

SiUS341802EC Troubleshooting by Error Code
Part 6 Service Diagnosis 270
Note(s)
Reference
3.23 Thermistor Abnormality
Applicable
Models
C4, C5 : All indoor units
C9 : except FXTQ-TA, FXTQ-TB, 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 275 for
C9
for FXTQ-TA, FXTQ-TB, and CXTQ-TA models.
CHECK 11 Refer to page 380.
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.
Remo v e the thermistor from
the indoor u nit control PCB,
and then meas u re the
resistance of the thermistor
u sing a m u ltimeter.
Normal?
Normal (The error is caused by
defective contact.)
YES
NO
Replace the indoor u nit
control PCB (A1P).
YES
Replace the thermistor ( 1).
NO
CHECK 11
Error
Code
Thermistor
Except
FXMQ-PB
FXTQ-TA
FXTQ-TB
CXTQ-TA
FXMQ-PB
FXTQ-TA
FXTQ-TB
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 —