What a difference There was soot packed all back in the heat exchangers and in a baffle just above the ash pan in the back.... It burns very clean now.... Right now I am running on heat level 2, on thermostat - house is 77 and holding in pilot mode since the thermo is only set at 72!! Its 40deg outside.... This is great stuff...heat pump hasnt run yet since I have had the furnace in....Eat it Penn Power!