Troubleshooting
Si10-417
32
Service Diagnosis
5.1.5 Thermistor or Related Abnormality
(Indoor Unit)
Remote
Controller
Display
C4, C9
Method of
Malfunction
Detection
The temperatures detected by the thermistors are used
to determine thermistor errors.
Malfunction
Decision
Conditions
When the thermistor input is more than 4.96 V or less
than 0.04 V during compressor operation*.
* (reference)
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
Faulty connector connection
Faulty thermistor
Faulty PCB
Trouble
shooting
Check No.6
Refer to
P.157
C4
: Heat exchanger temperature thermistor
C9
: Room temperature thermistor
Caution
Be sure to turn off power switch before connect or
disconnect connector, or parts damage may be occurred.
Check the connector
connection.
YES
Correct the connection.
Replace the thermistor.
(Replace the indoor
unit PCB.)
Replace the indoor
unit PCB.
Is it normal?
Is it normal?
(R1403)
NO
Check No. 6
Thermistor resistance check
YES
NO
Si10-417.fm Page 32 Wednesday, September 22, 2004 6:38 PM
