York YH9FYC18BAH-A-X Service Manual page 20

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.
10.3.2 EEPROM abnormal
E4: indoor EEPROM error
Indoor Display
Method of
The Data detected by the EEPROM are used to determine MCU
Malfunction
Detection
Malfunction
when the data of EEPROM is error or the EEPROM is damaged
Decision
Conditions
Supposed
Causes
Troubleshooting * Caution Be sure to turn off power switch before connect or disconnect connector,
10.3.3 Indoor AC fan motor malfunction
Indoor Display
E14
Method of
The rotation speed detected by the Hall IC during fan motor operation is used to determine
Malfunction
abnormal fan motor operation
Detection
Malfunction
Decision
when the detected rotation feedback signal don't received in 2 minutes
Conditions
Supposed ■ Operation halt due to breaking of wire inside the fan motor.
Causes ■ Fan motor overheat protection
■ Operation halt due to breaking of the fan motor lead wires
■ Detection error due to faulty indoor unit PCB
Troubleshooting * Caution Be sure to turn off power switch before connect or disconnect connector,
■ Faulty EEPROM data
■ Faulty EEPROM
■ Faulty PCB
damage may be occurred.
Replace the indoor or outdoor mainboard
damage may be occurred.
18
Service diagnosis
or parts
or else parts
Domestic air conditioner