What Causes Black Soot on Your Furnace Filter?

What Causes Black Soot on Your Furnace Filter?When changing the furnace filter in your Oklahoma home, you should look carefully for soot and a thick black powder that forms when the gas or oil that fuels your furnace is not being burned properly. Both scenarios can lead to poor indoor air quality, carbon monoxide poisoning and a risk of fire.

Large accumulations of soot often indicate that there’s something significantly wrong with your furnace, and you should immediately have a professional HVAC technician inspect your system. Here are a few of the most common causes of soot buildup on furnace filters:

Lack of Maintenance

At least once a year, you should have an HVAC contractor inspect your system and complete any routine maintenance that it requires. A lack of proper maintenance can lead to problems, such as soot production, inefficient operation, insufficient heating, clogged burners and a cracked heat exchanger.

Inadequate Fuel Delivery

Clogged oil nozzles or gas orifices can lead to improper combustion, causing the formation of soot. Household dirt or contaminated fuel is usually the cause, so you should have your HVAC contractor inspect the nozzles and clean or replace them if necessary.

Clogged Burners

Burners that are not adjusted properly or that are dirty can cause soot to form. Cleaning and adjusting the burners is part of the regular maintenance routine, but if you notice uneven or improperly-colored flames, you should have your furnace inspected as soon as possible. For gas furnaces, the flame should be blue, while for oil furnaces, it should be yellow.

Cracked Heat Exchanger

A cracked heat exchanger can allow combustion byproducts, including soot and carbon monoxide, to enter your air supply and distribute through your home’s duct system, which can be very dangerous. If you suspect a problem with your heat exchanger, have your system inspected immediately.

Improper Venting

Clogged or leaking vent systems or chimneys can cause improper combustion and soot buildup. If you spot a problem, have your venting system inspected.

To learn more about the causes of soot on your furnace filter, talk to our HVAC experts at Davis Air Conditioning. We have been serving the Southern Oklahoma region since 1976.

Our goal is to help educate our customers in the Lawton and Duncan, Oklahoma area about energy and home comfort issues (specific to HVAC systems).

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