Cause : Heat Sink temp comes when the maximum temperature of the heat sink has been exceeded. The temperature fault does not reset until the temperature drops below a defined heat sink temperature.

The trip and reset points are different based on the frequency converter power size.

• Check for the following conditions
• Ambient temperature too high
• Motor cable too long
• Incorrect airflow clearance above and below the frequency converter
• Blocked airflow around the frequency converter 
• Damaged heat sink fan
• Dirty heat sink : This alarm is based on the temperature measured by the heat sink sensor mounted inside the IGBT modules.
• Check fan resistance.
• Check soft charge fuses.
• Check IGBT thermal sensor.