Soot is a fine powder consisting primarily of carbon produced by the combustion process. Because of its extreme light weight, it fre­quently rises with the smoke from the fire and coats the interior walls of the chimney and flue. Although the heat loss from the insulating effect of a soot layer is small (generally under 6 percent), it can cause a considerable rise in the stack temperature. Soot accu­mulation can also clog the flues, thereby reducing the draft and resulting in improper combustion. Soot may be blasted loose from the walls of the chimney or flue with a jet of compressed air, or it may be sucked out with a vacuum cleaner. Another method is to use a brush to remove the accumulated soot layer from the walls.

Posted in Audel HVAC Fundamentals Volume 1 Heating Systems, Furnaces, and Boilers