I like my 25pdv mfg date 6/04.It burns a light grey/white ash,never any black soot on the window glass,just the light grey ash.Pellet consumption is about 40 lbs.per 16 hours on higher settings(5-7)and I can get 24 hours on the low settings(1-2)My problem is that after 6-8 hours of burning on the higher setting I have a burn pot full of black/partially burned pellets.The flame height is still normal with good heat output,but I am not getting combustion of the pellets.Is this normal and just the nature of this stove?Or is there something I can do to eliminate this problem?I read on other posts to this forum about the bottom three buttons on the control panel.I checked and mine are 6-9-1 left to right,but if I understand correctly those setting only effect the low (1-2) settings.Any help would be greatly appreciated,Thanks.