The inverter is working correctly. Apart from a few error messages during the first two days, which have disappeared as I’ve adjusted the settings, it has now been working correctly for eight days.
I am concerned about the STATE 475 error, which has so far stopped appearing after I changed the country setting from ES (Spain) to 50Hz (generic 50Hz grid). This error is related to the insulation between the solar panels and earth. I have tested the insulation between the DC circuits and earth, obtaining a value indicating full insulation.
I have two installations with the same inverter model. One from 2021 running on a Fronius Primo 5.0-1, and another from 2008 where I have replaced an old Fronius IG with the Fronius Primo purchased from Backmarket.
Next week I will try swapping the two Primo inverters, one for the other. If the STATE 475 error continues to appear in the older 2008 installation, it is likely that there is a fault with the installation itself. If the error persists on the same inverter, it is likely to be a fault with the inverter itself rather than the installation.
I’ll keep you posted.