Cause : THERM FAIL comes when drive internal fault or thermistor used for drive internal temperature measurement is open or short circuited.

The F0018 code in your ABB ACS310 drive indicates a thermal overload fault. This means the drive's internal heat sink has become too hot and exceeded its safe operating temperature.

Troubleshooting Steps:

1. Improve Ventilation: Ensure the drive is in a well-ventilated location with sufficient air circulation around it. Avoid installing the drive in confined spaces or near heat sources.
2. Clean Airflow Path: Clean any dust or debris accumulated on the drive's vents or heat sink. You can use compressed air (ensure the drive is off and disconnected from power) or a soft brush for cleaning.
3. Reduce Motor Load: If the F0018 code is accompanied by an overload fault (F0001), refer to our previous conversation on F0001 for steps to reduce motor load.
4. Check Cooling Fan (Advanced): Check drive cooling fan.