We have a comfortmaker furnace about 4 or 5 years old. We just bought house in april 2004. I noticed that the furnace cycles on and off three times before the thermostat is satisfied. The fan still is running the entire time the fire cycles off and on. The furnace is a 100,000btu for a 1500sq ft house ranch. Had a teck come out and check things. Everything checks out. He thinks furnace is to large for house and cycle switch for the fire box is telling it to turn off to cool and then bacl on again until thermostat is satisfied. He set the blower motor for high speed for heat and high for summer ac. So I was looking for another opinion. Any more info needed let me know.