Forget the damper in the pipe. You will only spend extra money on the damper and ruin a section of pipe. When the cat is running, the smoke going up the stack is so cool that you will want the extra draft anyway.
Pull the cover off the middle-back- top of the stove, between the fans and you can see the intake flapper. If this opens and closes when you move the air knob from minimum to maximum setting, then you are good. If the bi-metalic coil that controls the flapper is broken, this flap will stay shut. This system is time proven and very reliable, one of the best features on the B-K, once you get accustomed to it you will never go back to a manual control stove.
Forget the old way of controlling the fire with constant adjustments of the air intake. This works so well that I cannot understand why others stoves do not use it. It is not expensive technology, the old Ashley sheet metal stoves were some of the cheapest stoves on the market, and they had it. Most sheetmetal convection stoves also had it (pre-epa) So I do not buy the excuse that automatic controlled intake is unreliable or too expensive. It works too darn good to be without it.
Sure, its kind of fun making adjustments to a fire, but after a while it gets old, especially if it is your only source of heat and you want to go do something else for awhile without nagging doubts about the stove running amuck.
