Have HVAC Questions? Ask an HVAC Expert for Answers
Hello, so far it sounds like a printed circuit card going bad.
Has it been this way from the very beginning or did this situation develop later.
Use a hair drier to slowly warm the printed circuit card up to120For a bit warmer, but not over 140F... if there is any change in the error codes or other furnace behavior... the card has a cracked micro circuit that opens and closes as the card expands and contracts... that proves a bad printed circuit card.
No change however does not prove the card is good however... but any change proves the card is definitely bad.