So two 12v/3kw multiplus in parallel. Used System configurator to allow two separate inputs. Worked fine for a couple years. Today had a heavy load going on one multiplus input (46A). It dropped the grid input and went to invert. Troubleshooting showed there was power within spec at the AC-in terminals. Backfeed relay would click every few seconds, trying to connect to grid but never does. Troubleshot by applying grid power to other Multiplus (with the same configuration file), which connects to grid and operates fine.
I'm near certain the backfeed relay is dead (burned contacts). Just to verify my troubleshooting, anyone have any other ideas what went bad? Is this common?