What is an adjustable flue damper good for?

[ttyR2]

When I installed my used Blaze King Princess wood stove in the shop, it came with a damper in the used chimney pipe. I didn't install it, using straight pipe all the way up (including the triple wall). If I close the air intake control, the fire dies down but keeps going and doesn't cause much smoke, and no smoke coming out the door when adding wood.

So what is an adjustable flue damper used for exactly?

 

[woodchuck357]

There is no real reason for one, except to shut off air from below if you have a flue fire. It gives some people something to fiddle with. If your fire dies down to coals and the draft is left open AND the damper gets completely closed, coal gas can flow into your house and kill you or blow up the house.

 

[blades]

In some cases it is a method to reduce the draft of the flue. There by extending the burn time if used properly. The popular marketing phrase of sealed combustion is not true as there are always uncontrolled intakes for combustion air on most stoves. In the case of wood furnaces particularly the less pricy units from the box stores it is likely a better choice than a barometric damper as that introduces additional air into the flue cooling it creating better conditions for creosote production on units that already excel at that.

 

[Fred Wright]

Flue dampers date back to the days of inefficient cast iron smoke dragons, before outer baffles and electric refrigerators. The idea of damping at the time was to lessen the amount of heat roaring up the flue and control stove temp.

Our US 2007B stove came with a damper built into the stovetop flue collar. The only times we've used it was the rare overfire - when a split starts roaring out of control for some reason. Damp down to get the burn back under control.

Otherwise, it stays full open. From what I understand, this stove is designed for best efficiency with no flue damping.