Thermistor Or Related Abnormality (Indoor Unit) - Daikin E-Series Service Manual

Troubleshooting for RA Indoor Unit
4.4

Thermistor or Related Abnormality (Indoor Unit)

C4, C9
Remote Control
Display
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
Decision operation∗.
∗ (reference)
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.
" Faulty connector connection
Supposed
" Faulty thermistor
Causes
" Faulty PCB
Troubleshooting
Check No.06
Refer to P.279
C4
C9
276
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. 06
Thermistor resistance check
Is it normal?
YES
: Heat exchanger temperature thermistor
: Room temperature thermistor
NO
NO
SiENBE18-621
Correct the connection.
Replace the thermistor.
(Replace the indoor unit PCB.)
Replace the indoor unit PCB.
(R4696)
Troubleshooting