Rob R. wrote:The ash ring is the most critical, I wouldn't worry about a few pieces of black kn the ash. Trying to eliminate them usually sends more heat up the stack than you save from the ash.
Yes I agree as what I understand. The stack draft & over the fire draft are within the "acceptable ranges", st - .04 & ofd - .015. The ash ring is about 1.5 or 1.75 wide there about under full demand.
I think the decrease in unburned can be largely contributed to the air flow direction corrected. Also noticeable since correction is the center dark spot, reduced ash ring diameter to 1 to 2 inches, also much less clicker clumping in ash ring and ash bin. Of course this is coal from a different vendor, so I can't say if this is a factor.