As I have mentioned in the past, we bought a foreclosed Victorian "mansion" in the heart of the downtown of a small Minnesota village. This mansion had two heating zones, for which each had its own furnace. The furnaces were about 30-years-old and were being limped along by repairs every year.
This winter, one of them started pumping out some serious carbon monoxide out the exterior air vent. It was red-tagged and we had it replaced with a brand spanking new 96% forced-air furnace. (We had one of the water heaters go out then too, but that's another story).
So, after replacing that old dinosaur, we had one more furnace that needed to be fixed every few months or so. Until a few nights ago.
Minnesota decided to get a bit cold overnight. So, reluctantly, we turned on the furnace and went to bed. The air coming out of the vents smelled a bit like burning dust, but had a sort of smoky smell to it, as well. I shrugged my shoulders and nodded off.
At 1:34AM in the morning, our 13-year-old daughter stumbled into our room.
"Mommy. Daddy. Something is on fire."
I woke up with a start and rushed down into the basement, the smell of the fire pouring from the upstairs vents. Once in the furnace room, I found the remaining old dinosaur furnace's interior engulfed in flames. I quickly hit the emergency switch, shutting the furnace off, and watched until the flames died down and went out.
We then called the service guy.
When he showed up today, he flipped the furnace on and it started on fire again. He looked at my wife and said, "This is 100% pure carbon monoxide pumping into your ducts. Cracked air intake, etc."
Thank goodness our daughter woke up.