I have a Ravelli Roma pellet stove which is 1 year old. Last year I didn't have any problems but this year every time it goes to start up it fills with smoke and the combustion is so strong it shakes the stove and releases smoke into the room. Sometimes the combustion causes the baffle to fall out of place and hit the glass on the door. What could be causing all the smoke buildup in the combustion chamber and how do I fix it?