Flue gas damper

from Wikipedia, the free encyclopedia

A flue gas flap , smoke extraction flap or control flap or a smoke slide or chimney slide is a mechanically or electrically controlled device that can interrupt the air flow to the chimney behind the combustion chamber of a stove and its device for collecting the flue gas . In the case of a room stove , this is usually attached directly in front of the stove pipe connection and must be operated mechanically. In the case of a boiler , it is usually installed in the stove pipe to the chimney and is controlled electrically by an actuator .

The term stove door is also used colloquially , although this can cause confusion as this term is also used for the stove door.


A chimney draws the exhaust gases out of the furnace with the buoyancy of the gas column, which is lighter than the colder ambient air. This buoyancy of the heated chimney draws a stream of air through the furnace even after the end of the firing phase and leads the heat unused into the environment. Since the room temperature is usually always higher than the outside air, the effect leads to uninterrupted heat loss even when the stove is not in use . The function of the flue gas damper is to interrupt this air flow and the associated heat loss. To do this, it must be opened exactly when the stove is burning. If the mechanical furnace flap is closed too far during the firing, there is a risk of smoke gases entering the room if the furnace door is not completely airtight. In boilers with an electric smoke extraction flap, the heating control guarantees that the flap opens and closes on time.