Need help! I have a Buderus boiler with a honeywell electronic aquastat. I am off grid solar with a Honda 6.5KW back up generator. The boiler works fine while inverting off the batteries, but the control locks out on a Err4 when the generator is running. I see 125V at the control while on the generator. Everything is wired properly, grounded. I have tried a few thing with no change Switched L1, L2 and additional grounding. Thanks