As we are coming up on our 4th season heating with our US Stove 6100 furnace I contacted US Stove about what parts/gaskets I needed to eliminate their know soot issue and just figured it was time. After sending pics, reciepts, dates, times and a small dna sample they quickly informed me that my install was not only wrong but dangerous. I apparently have too much horizonal run. I spent $1200 on a "professional" install from our local hvac dealer. I have had the manual open 700 times but never bothered to read the specs on a proper install. After spending the long dollar on a install I never imagined i would have to. Now we are waiting for them to come and reinstall. Just a few words of advice for all those others that assume their contractors know wtf they are doing. inspect what you expect!!