Attached is a photo of my Regency I2400 insert. I did three break in fires last week. I am very happy with the way it burns as it really throws the heat. A ceiling fan has been added to the room also. One annoying problem was noted however.. Shortly after lighting the fire with kindling and small logs, say ten minutes or so, as I closed down on the dampner, about half way, the stove produced an annoying air vibration noise. When I opened the damper a little beyond half, the noise disappeared. As the unit warmed up and regular sized logs were loaded, I could close the damper to half without any problems.. Is this normal? Thanks again for all the information on this site.....Jim