Great forum. Thanks to everyone here. I am new to burning pellets and this forum has been a great source of info. Thanks to the search feature, I have had all but one question answered. I bought a Mt. Vernon AE 2 weeks ago. It is actually a 2006 model, but despite all I have read about the early models, it has worked well. On high it seems to have too much flame and the height adjustment has little or no effect and at the same time I get the humming/resonance noise I have read about. But since the stove rarely fires on high in the automatic setting where I keep it most of the time, I haven't been too concerned. I know a newer board/wall control will probably tale care of this. The dealer is a friend of mine and I might ask him to look into it. The one thing I would like to know is this: I found a 4-position rotary switch on the control board (visable from underneath the stove) and can find no info on it. There is a knob in the center of the board with a slot in it and an arrow pointing to: 0 1 2 3. It is now set on 0. Anyone know what this is?