Don't know the answer but looking at an image of the control board there appears to be relays on the board and there is one directly above where the fan connects to on the X7 plug connector.
You may have to remove the board and then follow the appropriate traces from the X7 connector, pins 1 & 2 and check where they go. If they connect to a relay then check the relay connections on the solder side of the board. If they appear to be electrically OK and not a dry joint you may have to check by tracing the relay's operate path to see if that is OK.
I couldn't find a schematic for the board (is it a mf08fa.1 as shown in the owner/service manual?) which would make it easier, but there are replacement boards available online when searching for Ferroli DOMICompact F24B mf08fa.1 if you decide on replacing the board.
If you spot something amiss on the board or are not quite sure, post some images back here. Here’s how to do this Voeg afbeeldingen toe aan een bestaande vraag