I purchased a Harman P61A pellet stove new five and a half years ago and it had been running flawlessly for the first five years until the middle of the winter last year. We burn approximately two tons per year.

Last season, it started giving us problems when it fed pellets into the burn pot - sounded like something was binding and a couple of times, the stove actually shut itself down.

After taking things apart for a thorough cleaning, and at the recommendation of my dealer who sold me the stove, I removed the auger to find that the tube had developed a lot of buildup (looks like black carbon deposits). I cleaned the tube thoroughly with a wet rag, and also cleaned up the auger so that it looks like new. I also noticed that there are two holes in the top of this tube directly under the hopper where pellets drop down - these were completely clogged with gummy sawdusty material. I cleared both holes, but the binding hasn't gone away.

After another thorough cleaning and inspection this past weekend, I've concluded that the problem has to be with the slide plate. I believe that it is installed correctly (slot facing up toward the hopper), but I'm wondering if I have more buildup inside the box in which the slide plate operates. Unfortunately, that "box" appears to be welded shut, so I don't know how to clean it.

Does anyone have any suggestions for how to clean that box? I cleaned the slide plate, but I suspect that there may be buildup that is preventing the pellets from dropping freely after the plate pushes them where they need to go.

Anyone else having this problem and does anyone have any solutions?