Have HVAC Questions? Ask an HVAC Expert for Answers
Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.
If you're talking about the draft fan then if you have established a call for heat and you have power to the board then the board is suspect. There is one other possibility that you can eliminate by jumping the R & W terminals on the furnace thermostat terminal strip. If the problem persists then the board is the likely culprit.
If I was at your place and found what you describe I'd replace the board but I'd check to be sure there is 24 volts at the trans former secondary before I went for a new board.