Sorry...clarify this for me please. Cat stoves have, on average, much lower particulate emissions. Is the by pass sealing? How long is by pass left open? And more...
Love my BK and would never go back to the non-cats for primary heat but here's the truth:
My current NC30 barn stove blows a 1.63 gph.
(broken link removed to http://www.heatredefined.com/englander/stove/englander-1800-2200-sq.-ft.-wood-stove)
My previous house stove the Hearthstone Heritage blew a 2.77 gph.
http://www.hearthstonestoves.com/store/wood-products/wood-stoves/heritage
My current BK princess house stove blows a 2.42 gph.
(broken link removed to http://www.blazeking.com/EN/wood-princess.html)
So the BK makes above average pollution in my case. Add to that the fact that the flue temperatures run nearly half as high as the non-cats and you have a recipe for greater flue deposits. Plus, in my experience and in the experience of other members, the flue deposits of the BK are blacker and thicker than what the inefficient non-cats put out. I might mention that I tend to burn on low settings 90% of the time which is supposed to be the cleanest and most efficient setting, it's also the magical setting for the BK.
The good news is that many folks have converted from non-cat to BK. I don't know any that would go back, they're that good. It also means that plenty have experienced the increased flue deposits and that new converts should expect it too. Other cat stoves burn hotter, less efficient, and reportedly have less flue deposits which is fine if you don't mind the shorter burn times.
To your other questions, yes the bypass is sealing. The gasket is evenly compressed and the bypass cams over with a satisfying click to lock it in. Bypass is left open until the cat probe is well past the active line. My stove was installed with a flue length that matched the manual, 12' total, but since then your manual has changed to require 15' for new stoves.
Stove is great. Wood is 2 to 3 year seasoned softwoods. Members should expect moderate amounts of black creo when sweeping a chimney above the BK.