Woke up this morning to find the house at 60 degrees. No heat.
Checked the furnace and found that the door had vibrated loose and door switch had cut power. Fixed that, but then had a 3 flash error code and no heat.
Some months ago, I noticed 2 electrolytic capacitors on the control board were swollen. Being in the electronics repair industry, I've seen PLENTY of those, so I was not surprised, just disappointed that they used such cheesy parts in something that should be reliable. In any case, one of them failed completely when the furnace was powered up. I had ordered some new high quality conductive polymer caps to replace them a long time ago and never did.
Lesson learned. Check your control board for this. They're obvious. The tops of them, which should be flat, are bulged. Replace them. It will save you a headache! :thumbsup:
You can see a picture of one of them here. It's right in the center of the pic. It's a bit hard to tell, but the top is bulged out a bit.
http://i1071.photobucket.com/albums/u516/pcbman_photo/HPIM1175.jpg
Cheers!