I'm not sure what's going on with the pellet stove,the burn pot overflows after couple hours. The air intake is clean. Nothing interfering,the door seal it's in perfect condition. I did the bill test. The stove has 5 levels of heating. Ii always have the stove on level 1, with the damper adjusted on 1/2 and it's still not burning all through the pellets. Looks like it's not receiving enough air in the burn pot. Here is the deal,I f I open the ash pan door the pellets burn completely and I don't have overflow and lazy flame, & when I close the ash pan door the pellets overflow and don't burn completely.