I am having a problem this year with unburnt coal in the ash pan and at first I thought it was the coal. However when I break open the unburnt pieces it indeed is coal. The reason I say this is because it is shiny and glass like.
I took the time to ensure that the grate is sealed with a new gasket, I tried cleaning the holes out with a drill, and I also gave the outlet pipe a good cleaning. After all of this I still am having unburnt coals in my ash pan.
The Old Mill is alot different I think than most of the stoves on this forum...or maybe not. It is a small paddle. I spoke with Jerry, formerly of Leisure line a few years ago and he said that the OLD Mill was the early design for the Alaska Stove., however the feed design was sub par at the time and has since undergone many improvements. I have discovered that when I have my MAX set at say 85, the burn area will only be about 4-5"s in length. If I go any higher it doesn't get any larger. It just kind of clumps up.
Today I have my MIN set at 15, and my Max set at 75.
It seems the combustion fan is OK, however I am wondering if maybe it is time to replace it to get more airflow. Someone said on this forum that they believe my stove is only rated at 55,000 BTU. I have been heating the downstairs at 73 degrees pretty well despite the unburnt coal issue.
I'm thinking maybe I am pushing too much, too fast onto the grate since it bunches up rather than make its way down the grate. Therefore alot of coal moves out past the burn area too quickly. However, if I lower the MAX to any lower than 70, then the stove has a hard time maintaining the temperature overnight. I may be up to a 3 degree difference.