No cooling airflow

This signature means that during a fan test, no air is pulled in at the inverter ventilation grids and no air comes out of them. To check, start the fan test from the inverter user interface, set it to the heat sink fan, and watch and listen at the ventilation grids. Set the test back to Off when you are done. Listen for unusual noise from the external fans during the same test, because it points to the same problem. Several inverter manuals call a cooling fan failure found by visual check an external fan error alarm, and some list an internal fan error as a cooling fan failure too. Possible causes are a blocked fan, a fan past the end of its service life, or poor contact at the fan socket connector. Missing airflow can also mean the external fans were not installed correctly. Check the installation first and call service if the problem continues. For the alarm, one recommended first step is to watch for 5 minutes and see whether it clears by itself.