Haier U Series Service Manual page 77

7.4.4 Thermistor or Related Abnormality(outdoor unit)
This type of error is detected by checking the thermistor input voltage to the microcomputer.
(A thermistor error is detected by checking the temperature)
The thermistor input is above 4.9V or below 0.1V with the power on.
Troubleshooting
Check the connector connection.
Is it normal?
Thermistor resistance check
Is it normal?
Replace the outdoor unit PCB
Thermistor resistance check method:
Remove the connectors of the thermistors on the PCB, and measure the resistance of thermistors using
tester.The relationship between normal temperature and resistance is shown in the value of outdoor
thermistor.
notes:
F6:Ambient temperature sensor failure
F7: Suction temperature sensor failure
F21: Frost-removing temperature sensor failure
F25: Exhaust temperature sensor failure
The values may vary slightly in some models
Faulty connector connection
Faulty thermistor
Faulty PCB
Be sure to turn off power switch before connect or disconnect connector,
parts damage may be occurred.
NO
YES
YES
Correct the connection
NO
Replace the thermistor
74
or else
Domestic Air Conditioner