My Accentra 2 pellet stove seems to be feeding too many pellets into the stove & they are not burning fully. I have had to turn the feed knob down to about "2". Is this just a simple matter of cleaning or is it the sensor? This stove was purchased in October of 2004. I am in the process of replacing the sprockets & chain when the weather warms up more. The stove runs 24/7. I only use oil to heat my water & usually only have to purchase one tank of oil a year.