Daikin FTX25JVEA9 Service Manual page 249

Troubleshooting - Split Type Indoor Unit
1.5.4 Operation Halt Due to Detection of Thermistor or Related
Abnormality
C4, C5, C9,
Remote
Controller
Display
Indoor Unit LED A
Display
Note: No LED Display on FTK(X)25/35J Series.
Method of The temperatures detected by the thermistors are used to determine thermistor errors.
Malfunction
Detection
Malfunction When the thermistor input is more than 4.96 V or less than 0.04 V during compressor
operation ∗ .
Decision
∗
Conditions
When above about 212°C (less than 120 ohms) or below about -50°C (more than 1,860 kohms).
Note: The values vary slightly in some models.
"
Supposed
"
Causes
"
Troubleshooting
Check No.8
Refer to P.305
C4 : Heat exchanger temperature thermistor
C5 : Heat exchanger temperature thermistor
C9 : Suction air thermistor
CA : Discharge air thermister
236
CA
5 B 5
(reference)
Faulty connector connection
Faulty thermistor
Faulty PCB
Be sure to turn off power switch before connect or disconnect connector,
Caution or parts damage may be occurred.
Check the connector
connection.
Is it normal?
YES
Check No. 8
Thermistor resistance check
Is it normal?
YES
NO
NO
Si18-201
Correct the connection.
Replace the thermistor.
(Replace the indoor unit
PCB.)
Replace the indoor unit
PCB.
(MF004)
Service Diagnosis