Having problems setting up a battery backup system for my furnace. Have 2 large 12v battery's connected to my inverter connected to my furnace. Furnace error code is open ground or reversed neutral. I checked the inverter shows open ground even with the ground connected to the grounding stake and water pipe!
This is the second inverter I got took the first one back, second one the same problem. This is a full sign wave inverter because the furnace will not run on my modified sign wave inverter! Any Help out there?