I’ve been getting a ignition fault message, I changed the transformer, and flame sensor today and it fired up, last week it was the ignition box same thing it fired up and ran for two days. I had left the front cover off today and when I went to put it back on it shut off. I took the cover back off and it stays on. Is there a vent that needs to be cleared and where is that? All I see it the vents on the back towards the bottom.