I talked to a former Thelin installer a while ago and he told me that the problem with my Gnome start/stop might be that there is not enough lift in the flue as it goes out through the roof. I have mine at the upper limit with 4" pipe. What I was wondering is if anyone has tried a flue fan of some sort to get more lift of the exhaust from the stove (or any stove) and how that worked for you. thanks.