Short SS Barometric Flue Damper - 4"Dia. x 7" Long

An adjustable barometric damper should be installed on all diesel or solid fuel heaters and stoves, and is especially recommended when the stove flue pipe is over 5 or 6 ft long - a situation where excessive draft is likely to be a constant problem.
The barometric damper helps decrease the draft on longer chimneys allowing the user to operate the unit at lower fuel settings - saving heat, fuel, and money.

This particular damper is installed in a short (7 or 9") piece of flue pipe with a 1" crimp at one end for making connections. It is designed to be installed immediately after the first section of flue pipe attached to your heater or diesel stove.

• Especially recommended for flue lengths over approximately 5-1/2 ft
• Stabilizes draft in gusty wind conditions
• Available in 3", 4", and 5" diameters
• Pipe is 304 stainless steel, damper is painted black

Barometric dampers are also available already installed in a 24" length of flue pipe - putting them at the ideal location of 12 - 20" above the heater; see Related Products, below.


Heavy on the technical side...

For optimal performance - stable heat output and efficient fuel consumption, the "draft" or suction created by rising hot exhaust gases in the flue pipe of a diesel or solid fuel stove or heater, should remain constant - not too high, not too low.
By opening and closing in response to changing draft conditions (gusty winds, daily outside temperature fluctuations), barometric dampers - also called draft regulators - stabilize the stove chimney draft.

You can think of it as an airflow "relief valve". As draft increases, the flap of a barometric dampers automatically swings open wider, drawing "room air" into the flue and reducing draft. Thus, they prevent problems casued by excessive draft - such as erratic burning, overheating, and wasted fuel.
Conversely, if the draft decreases, the flap closes to reduce room air intake, increasing the flow of hot exhaust gases from the combustion chamber to maintain ideal draft conditions.
The proper adjustment of barometric dampers is integral to their functioning and is accomplished by turning the knob on the outside of the damper which, in turn, moves small balancing weights on the inside. Correct adjustment of the damper is typically determined by measuring the temperature of the flue pipe.

In some stove or heater installations where the flue needs to be very long in order to vent gases to the outside, excessive draft can be a constant problem - as it is "built into" the system. A barometric damper is the ideal solution for this problem as it has the same effect as shortening the flue - achieving an ideal combustion rate and saving fuel, heat, and preventing unsafe overheating of the flue pipe.