OK, last winter our furnace stopped working. We called in repairmen and they fixed it. Then a month later, when we'd turn it on, you could hear it start up but it wouldn't blow any air out. They came back and fixed it by replacing the thermostat which they said was wired wrong. No trouble all summer/fall. Now it is winter again and the furnace is doing the same thing= Turn it on & you can hear the fan running/trying to run, but no air comes out and it shuts off (the gas is not lighting up when its doing this), then in a couple minutes it tries again. Over and over. Seems like it has to drop the overall house temp 8-10 degrees before it will start working again.
The furnace is a Trane and is 14 years old.