I hope someone can help with somewhat of a problem I have been having. My Summers heat 55-shp22 has been working great for me, but I seem to be having "dirty" burns. I was reading somwehere that the ash should be greyish-white. I do not have any clinkers, but the ash is a dark brown to black color. I am somewhat concered that my venting might be the source of the problem. I have a 4inch vent pipe with a 3in adapter that was installed to a whitfield before I moved into the house. Thankfully everything fit nice when I upgraded to the Summers Heat/Englander. The vent runs vertical for I'd say 5-6 feet then ends with a 90 degree elbow. I was thinking that if I adjust one or all of the buttons of the bottom of my unit, it would help. Currently my stove is set to: Low fuel feed-5 Low burn air-4 Air on temp-1 I am just not sure which way to go with them, or keep them all the same. Thank you for all your help! I saw a post on here sometime ago that detailed exactly what the settings dictate, but could not find it in my search today. Thanks to anyone who can help me out!