Our furnace stopped blowing hot air we called a tec and he replaced the pressure switch and it worked intermitly. He said the board was bad also and wanted anouther 435 to replace it also we just didn't have the cash to do it so it went all the way out last week. I ordered a new one on eBay for $100 and put it in myself. But same prob. Small fan runs not the big one and no flame. Please help it cold here in Idaho Also the led light stays on saying that it isn't detecting a problem and the ac works fine