Hi, I recently installed a Colonial TR004 wood burning insert with a 24 foot insulated stainless steel liner mounted inside an exterior chimney. I am concerned as to whether my air control lever (a.k.a. damper control) on the front of the insert is working properly. In the open position it is a little hard to get the fire started without leaving the door ajar. I understand this is pretty common. I leave it in the open position and the fire eventually really gets going with a nice clean burn. However, closing the air control lever seems to have little or no effect. If I open the door slightly the fire clearly gets more air. My question is "does this sound normal"? Should sliding the air control show a clearly noticeable change in the fire? I worry that my air control lever is not working.