Our furnace is a Bryant 90 High Efficiency (power vent) and it is about 18 years old. When the furnace is switched off then on (from either the power switch or thermastat) it will run one complete cycle without any problems (the burn piece of the cycle is about 5 minutes) then everything shuts off and doesn't re-start. If I run a self test on the furnace, it cycles through each of the components successfully. The problem is that it simply will not re-start on its own (even though the temparature is 20+ degrees below the temparature on the thermastat).
I had the furnace specialist out (and paid the $145 for 45 minutes of looking) and was told we need a new furnace. I'm not ready to give up yet. All of the pieces cycle correctly, but only once. Unfortunately, only my wife was home when the furnace person was there. According to the bill he cleaned some leaves from the intake and made some adjustments. The carbon monoxide reading he took was 20 ppm and he said it went down to 16 ppm by the time he left.
Due to the elevated carbon monoxide reading, I assumed that clogging of the intake pipe may have really been an issue, but even after whatever the HVAC guy did, the furnace behaves exactly the same.
I know my furnace is on the old end, but I would like to squeeze another winter or two out of it if I can.