Question: I had a Quad 1200 as primary heat source, and was reasonably happy with it for a while. The problem arose when it just did not put out enough heat, and when run on high 24-7, was making clinkers the size of grapefruits and generating huge amounts of ash. On top of that, the vent pipe got ripping hot, which lead me to question how efficient the stove was if so much hot air was going up the chimney. All I ever used were premim pellets from Lignetics, Energex, Dry Creek, etc. Anyway, I put in an order for a Harman P61A; Harman claims their bottom feed setup pushes clinkers out of the way, generates less ash, and that their exhaust temps are much lower than Quad. I don't like the idea of heat (and dollars) going up the chimney. Would it be worthwhile to install a 3 inch to six inch adapter, use 6-inch woodstove venting pipe, and install a heat extractor, or should I just go with pellet pipe? Answer: The pipe should be kept small....3 or 4 inch. If you wring too much heat our of the flue gases, they will condense and cause untold problems including corrosion and excess moisture (ice, etc.). It is true that the bottom feed can easily push the clinkers out of the way. I used a Harman pellet unit years ago and was impressed by the mechanism.