Functions and Applications of Draft Regulators and Barometric Dampers
Draft regulators and barometric dampers are a common component of oil fired heating equipment. Barometric dampers are located in the flue vent between the source of heat and the chimney system. The regulator is T-shaped with the face of the "T" containing a small door that has an adjustable weight attached to it. Adjusting the weight requires specific measurements of the internal draft inside the oil fired heating appliance. It is highly recommended that you have an experienced Heating, Ventilation, and Air Conditioning (HVAC) expert make any adjustments to your barometric dampers' settings.
Barometric dampers and draft regulators are used to regulate airflow in oil fired heating appliances. Examples of common household items that contain barometric dampers and draft regulators are furnaces, boiler systems, and water heaters. A barometric damper works by regulating pressure inside the appliance. Just as a barometer measures pressure in the atmosphere a barometric damper measures the pressure of the air inside the appliance and the pressure of the free air in the room.
When oil fired heating equipment is in use, free air moves through the doors in barometric dampers into a combustion chamber. This air helps to fuel the combustion processes and builds up pressure inside the heating appliance. This pressure then forces the air to move through the appliance and into the chimney system. The amount of force that is produced by the internal combustion in the combustion chamber is the "draft" we have been referring to.
How efficiently appliances use energy is a direct function of barometric dampers and draft regulators. Whenever the pressure of the air outside of barometric dampers is greater than the pressure inside the oil fired heating appliances this is referred to as "negative" air pressure.
If the pressure of the air outside of the barometric damper is greater than the pressure inside the appliance the doors of barometric dampers open because the adjustable damper weight attached to the door. This restricts the flow of air into the damper until a balance is reached and then the door returns to its normal position.
However, if the pressure inside the appliance is greater than the free air pressure the damper door will close. This allows the air inside the appliance to be expelled through the chimney system until the pressure drops and the door once again returns to its normal position.
Barometric dampers act as a stabilizer of the draft that is drawn into the flue vent from the free room air outside the appliance. The reason for this is because when the draft pressure is to high it reduces the efficiency of the entire oil fired heating system. This reduction in efficiency is manifested in wasted fuel and unpredictable burning since the system is no longer in balance. Barometric dampers and draft regulators operate automatically.
Making sure your barometric dampers are properly calibrated in your heating appliances is important. These draft regulators enhance combustion so that the entire system operates more efficiently and predictably. One of the newest developments in the barometric dampers is the "field barometric damper" which features enhanced sensitivity settings and durable construction.