Thermistor Abnormality - Daikin VRV RXYQ72-384XAYCA Service Manual

Troubleshooting by Error Code

3.23 Thermistor Abnormality

Applicable
C4, C5: All indoor units
Models C9: except FXTQ-TA, FXTQ-TB, and CXTQ-TA models
CA: FXMQ-PB models only
C4, C5, C9, CA
Error Code
Method of Error
The error is determined by the temperature detected by the thermistor.
Detection
Error Decision
The thermistor becomes disconnected or shorted while the unit is running.
Conditions
Supposed
 Defective thermistor
Causes  Defective indoor unit control PCB
 Defective connector connection
 Broken or disconnected wire
Troubleshooting
Note(s)
1. Error code and thermistor
Error
Code
2. Refer to page 274 for C9 for FXTQ-TA, FXTQ-TB, and CXTQ-TA models.
Reference
CHECK 11 Refer to page 366.
269
Be sure to turn off the power switch before connecting or disconnecting
Caution connectors, or parts may be damaged.
Remove the thermistor from the
indoor unit control PCB. Then,
insert the connector again.
Is the
thermistor normal?
NO
Remove the thermistor from
the indoor unit control PCB,
and then measure the
resistance of the thermistor
using a multimeter.
CHECK 11
Normal?
YES
Thermistor
C4 Indoor heat exchanger liquid pipe thermistor
C5
Indoor heat exchanger gas pipe thermistor
C9 Suction air thermistor
CA
Discharge air thermistor
YES
NO
Except
FXMQ-PB
FXTQ-TA
FXTQ-TB
CXTQ-TA
R2T
R3T
R1T
—
SiUS342004EB
Normal (The error is caused by
defective contact.)
Replace the thermistor ( 1).
Replace the indoor unit
control PCB (A1P).
FXTQ-TA
FXMQ-PB FXTQ-TB
CXTQ-TA
R2T R2T
R3T R3T
R1T
2
R4T —
Part 6 Service Diagnosis