I have just installed a fpx 44 elite sometimes when I open the doors it lets smoke in the house. I don't know what is wrong I always open the damper and wait 30 seconds or so before opening the doors. It does not let smoke in the house every time but it is enough to make the wife a little mad. Does anybody else have this problem or is it just me? What could be the problem I have 24 ft of chimney pipe with no bends in it ? Any help would be appreciated.