Puff Backs: When Furnaces Attack

There are approximately eight (8) million homes that use heating oil as their primary source of heat in the U.S., and 80% of those homes are located in the Northeast. Many of these homes experience a “Puff Back” – a malfunction in the heating unit resulting in soot being expelled throughout parts, or all, of the home. Lack of regular inspection and service of the heating system poses risks suck as loss of heat or, in some cases, a messy and dangerous puff back.

A furnace puff back is an actual explosion of unburned fuel in the combustion chamber of the furnace.   The extent of this damage and the amount of soot expelled depends on how much unburned fuel there was in the chamber. There are two major malfunctions that can cause this fuel to accumulate:

  1. Leaks in the fuel supply line, which can cause air bubbles to form in the fuel supply. These bubbles can than cause fuel to drip into the combustion chamber while the system is off, accumulate, and ignite when the system starts up. Depending on the amount of fuel, this ignition can create a loud bang along with the explosion of soot.
  2. Problems with the supply lines and valves that leads to an incomplete shutoff of fuel supply. When the heating system shuts down, a valve in the supply line closes to prevent additional fuel entering the combustion chamber. If the valves are corroded, or if there is dirt or debris in the valve area, it can prevent the valve from completely closing. Again, this results in unburned fuel in the combustion chamber that builds up until the system is turned on, resulting in an explosion.

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In the event you do experience a puff back, you may notice black or brown streaks on the walls and ceiling. The soot will tend to settle on cooler areas on these surfaces such as nail heads, corners of these rooms and where the framing is behind the finished surface. Soot will also settle on flat surfaces such as tables, floors and furniture. If you notice these clues in your home or business, do not attempt to clean yourself.

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Depending on the type of fuel and surface being cleaned, more damage could be caused by not cleaning the correct way or with the incorrect cleaning agent. Instead, contact your insurance company along with a reputable professional restoration company. They will work together to get your home or business back in order, which may include a thorough cleaning of your home/business, the contents and textiles (clothing/drapes/bedding), deodorizing of the building, and possibly painting of heavily damaged areas.

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