I have a Trane XL80 furnace. The burners ignite and the furnace works great. At the end of the cycle when the burners turn off, the fan runs for a minute or two until all of the air is expelled. Problem is, sometimes at the end of the cycle (not always) the blower never stops running and a new cycle never begins, just blowing coolish air. If I shut off the blower using the switch mounted near the blower and then turn it back on, a new cycle begins and it works fine, but then again, the blower runs and runs and slowly but surely the temp in the house goes down until I go shut off the blower and start the cycle again.

Please help, it's cold here

Mick Mpls MN

You are reseting the circuit board if your unit is so equipped. This can happen if the flame sensor is dirty. Try cleaning it with fine sandpaper or steel wool. If this does not do the reick post back.