Fan fault

What does FN mean?

This alarm indicates a problem with the inverter's cooling fan. It appears on the operation panel when the cooling fan stops due to an alarm condition or operates differently from the settings configured in Pr. 244 (Cooling fan operation selection). Insufficient cooling can lead to inverter overheating and potential damage to internal components.

• Cooling fan motor bearing failure leading to seizure or increased friction.
• Accumulation of dust and debris on fan blades, reducing airflow and causing overload.
• Control circuit fault for the fan power supply (e.g., failed relay or transistor).
• Fan speed feedback signal loss or incorrect reading if fan is equipped with a speed sensor.
• Inverter internal temperature exceeding threshold (e.g., set in Pr. 100), triggering a fan override fault.

Click steps to track your progress.

1. 1

   Disconnect main power supply to the inverter and wait for DC bus discharge (measure terminal V+/V- for 0VDC).

2. 2

   Open inverter enclosure and visually inspect the cooling fan for debris accumulation or physical damage to blades.

3. 3

   Manually attempt to rotate the fan blades to check for free movement and bearing resistance.

4. 4

   Measure the voltage at the fan power terminals (e.g., F+/F-) on the control board while the inverter is attempting to run.

5. 5

   If voltage is present and fan is not spinning, replace the cooling fan unit with an OEM approved replacement part.

6. 6

   Verify fan operation and internal temperature readings (e.g., Pr. 100 or Pr. 101) after power-up.