Thanks for your help. I know the polarity is correct. There are 2 ground rods plus an underground copper gas line between the generator and the furnace. What do you guys think about running the control circuit with a pure sine wave inverter? If I use magnetic contactors hooked to the control board to run the furnace motors and ignitor, i can get down to about 2 amps, thus reducing the size (and expense) of the needed inverter.
