I have a luxaire hvac, and the control board was replace this summer. The installer told me that the heater would not work because of a polarity swap... said the new boards sensed this and prevent operation. The red fault light blinks 9 times, code says "grounding or line polarity fault"

I checked the inputs and the black hot' wire measured 120vac. The white neutral wire measured 0vac and resistance to ground is 0. This is an old house and does not have ground wire coming from main ckt panel to luxaire.

On the control board, the black wire goes to connector labeled "L1", and the white wire goes to connector labeled 'neutral'

Part numbers from the new control board is Source1 are 539617 and also has these: 1152 1162-201

AC works fine, it is just the heater, will not start the burners.