I have a Rudd system. The problem is the draft inducer turns on, the pilot lights the burners, the furnace fan turns on and runs for 8 minutes. The furnace and burner turn off but the draft inducer stays on. The burner relights, the furnace turns on and runs agian for 8 minutes. The system will do this several times until the temperture in the house goes up 2 degrees higher than the thermestat. Then it will finally shut down everything and stay off until the house cools down to about 2 degrees lower than the thermestat is set at. The system use to run continuesly until it eached the set temperture. What could be wrong?