The pellets in the firepot do not all burn up to ash some are burnt but not completly. Turning the damper up or down mahes no diiference. I have 3ft of pipe thru the wall with anot6her 3 ft to extend beyond the house. The middle of the house is set in so you have a room that extends out on each side bldg inspector wanted it extended thats why i add the second 3ft pipe hope I have explained my situation to you,on a low setting the stove burns up pellets to quick and fire almost goes out any suggestions