How to Adjust a Barometric Damper on Your Furnace

A barometric damper is also known as draft regulator. Its function is to regulate draft on furnaces, boilers and heaters that use oil as the main source of fuel. The best position to install a barometric damper is in the flue vent between the heater or furnace and the chimney. It contains an adjustable weight which is manipulated to control the amount of air entering the chimney during combustion.

Step 1 – Check Installation

It is important to make sure that barometric damper is installed correctly. Check that the “tee” is positioned between the furnace and chimney. This allows it to perform efficiently while controlling air supply. It should be placed in an upright position on vertical or horizontal flues.

Step 2 – Making Adjustments

On the surface of the device, locate the weights and scale. Normally, these should be adjusted according to manufacturer burner’s instruction. There is a standard number provided by manufacturers when the burner is operating at normal temperature. Check these readings so as to make correct or very precise estimates when making adjustments.

Step 3 – Weight Setting

Three sets of adjustments are made to control the device. These include draft over the fire, draft in breech and carbon dioxide measurements. Always pay attention to carbon dioxide readings as they show how complete the combustion process takes place.

Step 4 – Positioning Weight

    To make adjustments, move the weights along the scale to the required level. This controls how much the draft regulator door opens to let in air. This is also depends on the three measurements; draft over fire, draft in breech and carbon dioxide. Make sure to move the weight correctly so as to provide effective condition that will support combustion.

    What You Need to Know

    Learn when to make adjustment on the device, this will allow the oil furnace to work optimally at all times. A barometric damper enhances safety standards in the home too, an efficient furnace vents out gaseous wastes from combustion such as carbon dioxide and carbon monoxide. If these are not vented safely, they can easily accumulate in the home and cause toxic air and illness.

    Setting or adjusting a barometric damper correctly reduces back pressure in the fireplace. Backpressure can cause the furnace to overheat or develop other problems which might interfere with its operation.

    Correct adjustments on the device helps to conserve energy and fuel in the home. It is possible to lose heat from the furnace if the adjustment is made with the flue draft positioned too high. In this case, the furnace might not provide heat as needed.


    • Handle barometric damper with great care
    • Take care of the device during cold and rainy seasons as it can easily get damaged
    • Set the damper to support a low draft at all times, this allows the furnace to work efficiently