Question: Flu collar is 8 inch which I had to reduce to seven just before the chimney connector. The stove -chimney has a good draft, but makes a chugging sound, which is reduced in intensity when the flu gets warmed up. There is no window in the stove, and if I try to open the door to check the fire status the draft tries to pull the door shut out of my hands, but does that off on chugging as it pulls. Would a fresh air hookup do something about this? Answer: Your draft is probably too strong....A turn damper or barometric damper in the flue will slow down ort even out your chimney draft and cure the problem.