Field Controls 02722701 Draft Control, RC, Stainless Steel, For: 15-3/4 to 22 in Dia Pipe

The Field Type RC draft control is furnished as standard equipment on many leading brands of oil or coal-fired heating equipment. The Type RC is calibrated to allow for easy adjustment to the furnace or boiler manufacturer's specifications. Designed for settings from 0.02 to 0.08 in, this control is so sensitive that instrumentation should be used when adjusting the unit during installation. How do draft controls work? Static pressure of the cool air exerts pressure on the outside of the furnace or boiler, the breaching and stack. The pressure difference between the room air and heated gas (air) causes products of combustion to flow (draft) through the unit and rise through the breach and chimney. Room temperature air enters through the barometric draft control in the precise amount needed to overcome the excess drafts caused by temperature variations, wind fluctuations and barometric pressure changes. Combustion of fuel is complete and the process is stabilized. The velocity of combustion gases through the heat exchanger is slowed so more heat is extracted. The unit operates more efficiently, reliably and requires less maintenance. Why do you need a draft regulator? Air used for combustion is called combustible air and may be in the boiler room or delivered by mechanical means. This air is combined with the fuel and is part of the combustion process. The gases that are produced must be discharged back to the outside environment. The gases moving through this process is called the draft. Too much draft will decrease the efficiency of the heating appliance, increasing cost and increase chimney temperatures to an unsafe level. Too little draft can result in incomplete combustion, soot, puff backs and in an extreme case, carbon monoxide. Since the chimney draft varies greatly, there needs a way to stabilize it and that is what the draft regulator does.