York YH9FXC24BAH--FX Service Manual page 37

Caution Be sure to turn off power switch before connect or disconnect connector, or else
parts damage may be occurred.
11.4.1 Thermistor or Related Abnormality
Indoor Display E1: Room temperature sensor failure
E2: Heat-exchange sensor failure
Method of The temperatures detected by the thermistors are used to determine thermistor errors
Malfunction
Detection
Malfunction when the thermistor input is more than 4.92V or less than 0.08V during compressor
D e c s i o i n o p r e t a
Conditions
Note: The values vary slightly in some models
Supposed
Causes
Troubleshooting * Caution Be sure to turn off power switch before connect or disconnect connector,
Check the connector connection.
Thermistor resistance check
Thermistor resistance check method:
Remove the connector of the thermistor on the PCB, and measure the resistance of thermistor using tester. The
relationship between normal temperature and resistance is shown in the value of indoor thermistor.
o i . n
Faulty connector connection
Faulty thermistor
Faulty PCB
parts damage may be occurred.
Is it normal?
Yes
Is it normal?
NO
Correct the connection
NO
Replace the thermistor
Yes
Replace the indoor unit PCB
35
Service Diagnosis
or else
Domestic air conditioner