I own a 1978 tri-level house that had a heatilator fireplace. A couple of years ago I installed a Appalachian 4n1-xl cat insert with 6 inch stainless steel flex liner and insulation. I seem to notice a smoke smell from the blower outlet and right below it by the door. I have noticed this ever since I got this thing and really haven't gotten an answer from Appalachian about this. I do not understand where it could be coming from other than the door. I replaced the door gasket and feel that it is a good seal, but maybe not. You don't seem to notice it much in the house, but you can smell it when you stick your nose by the blower outlet. It baffles me what it could be. I am tempted to replace the door gasket again with a bigger size. Any body out there have any idea where it could be coming from? Thanks in advance.