I have a St. Croix Hastings Pellets stove which I have been happily using for around 9-10 years. Over time, I've learned to take it apart and clean it like a pro, which usually solves any problems. This season it's giving me a problem that I can't solve. When it starts up, it feeds way too many pellets into the burn pot. After it runs for a while, the pellets in the burn pot eventually burn down to the right amount. However, as the day goes on it continues to gradually feed too many pellets into the burn pot. Eventually the burn pot over flows, the flame gets tall and lazy, and the glass door gets black. Attached is a picture. I've tried adjusting the pellet feeding flow using the auger trim button, but that is not working. Anyone have any ideas of what is going on here?