What does Bleeding a Furnace Mean?

In furnaces that run on oil, sometimes the oil becomes dirty and contaminated with dust, dirt, and other particulates. Continuing to utilize dirty fuel could compromise the safety, efficiency, and effectiveness of the furnace. Furnace bleeding may also be done to get air out of the fuel lines in the event that the furnace runs out of oil to burn. Bleeding a furnace is done to get rid of the old, dirty oil so that clean fuel can be added to the system. The process is similar to having an oil change in a car. With this guide to furnace bleeding, you’ll learn more about the importance of this maintenance task and how frequently it needs to be done in order to ensure a properly operating furnace.

How Bleeding a Furnace Works

Bleeding a home’s furnace should only be done by an experienced heating and cooling service technician. The steps of the process are as follows:

• The furnace is shut off. Power is cut to the furnace.
• The technician locates the bleeder valve. After opening the valve with a wrench, air will come out of the furnace.
• A tube is connected to the fuel line valve.
• The technician turns the valve and presses the furnace reset button. Fuel begins to flow out of the furnace.
• If there are bubbles in the fuel, the bleed will need to continue until there are no more bubbles.
• Once there is no longer air in the fuel and the fuel is clean, the technician stops the bleed.
• Additional cleaning or refilling of the furnace may be needed before it’s turned on again.
• The technician may also change the furnace filter.
• Sometimes a thorough furnace bleed requires more than one cycle. The technician will check the furnace performance and determine if it needs to be bled again.

Benefits of a Furnace Bleed

Air in the fuel lines of a furnace can cause problems with the burning of the fuel. Bleeding the air out of the fuel lines can prevent such problems. Getting any air out of the fuel lines allows the furnace to operate consistently and start as it is supposed to. After your furnace is bled, you may find that its fuel consumption decreases and that the fuel burns more cleanly. After a furnace bleed, the furnace should cycle as expected and should operate more quietly.

A furnace bleed is a messy and time consuming process that should only be done by someone experienced in the maintenance and repair of oil furnaces. We clean up after we complete our work and we also ensure that the oil from the furnace is disposed of properly. If your Alexandria, VA furnace needs to be bled or it needs any other maintenance or repairs, contact our staff at Brennan’s Heating & Air Conditioning any time.