I have a weathermaker 8000 (carrier)... a few nights ago, I noticed that it was blowing cold air... went down, looked at the furnace, and found that the gas wasn't lighting (so no heat). A little further looking and I found the exhaust pipe had broken off--one section had caved in/fallen apart. I shut it off, went to the hardware store, replaced all the 4" exhaust with 4" type b aluminum piping. Before putting it into the chimney, I vacuumed out a large pile of ash in the 5" flue. Now, same story--inducer fan kicks on, but no gas/pressure switch. No glow, no gas (no smell of gas), and of course, no flame.

I did notice a lot of rust flakes had fallen into the fan--or rather, into the area before the fan, and I had vacuumed it out, but I did hear some dust in the fan as I started it up.

Model 58WAV091-14

Check the port that the pressure switch hose hooks to on the draft inducer. Make sure it is not plugged.