Can Furnaces Catch Fire?

The return of cooler temperatures raises your dependence on home heating equipment each fall. If your furnace isn’t working properly, it might become a fire hazard and threaten your family’s safety.

According to the National Fire Protection Association (NFPA), heating systems like furnaces are a top source of home fires, leading to approximately 50,000 blazes, 500 civilian deaths and more than $1 billion in direct property damage annually. Space heaters and fireplaces cause the majority of fires affecting heating equipment, but central heaters, like furnaces, are liable for around 12% of these blazes. Learn the primary causes of furnace fires and how to avoid them.

Causes of Furnace Fires

Older furnaces are more vulnerable to safety problems as they may be configured differently and settle into disrepair through the years. That being said, whether your furnace is more than a decade old or brand new, you should be aware of these causes of furnace fires.

An Overheated Motor

A furnace motor can overheat in different ways. Here are the biggest risks:

    • A clogged filter can block airflow and cause the motor to work longer. Sooner or later, the motor might overheat, elevating the risk of fire.
    • Dirt can accumulate around and cover up the motor, forcing it to hold heat, which can cause a fire.
    • Exposed or deteriorated wiring can cause the voltage to get too high, increasing the likelihood of an electrical fire.
    • Overly tight or worn motor bearings can heat up whenever the furnace runs. Without the appropriate lubrication, the bearings could eventually light on fire.

Clogged Furnace Flue

Yard waste, animal nests and other obstructions can obstruct the furnace flue, lowering oxygen. This causes soot accumulation and improper ventilation, limiting efficiency and raising the risk of flame rollout. Flame rollout is when fire escapes the heat exchanger and burns the parts in your furnace. If this problem persists, your heating equipment may be seriously damaged, and the fire may even spread to areas outside the furnace.

Obstructed Heat Exchanger

The heat exchanger is a restricted combustion chamber where the heat produced by your furnace is exchanged to the air circulating through your home. A heat exchanger clogged up with soot or corrosion has the same effect as a blocked furnace flue—reduced performance and a higher risk of flame rollout.

Cracked Heat Exchanger

Various problems can happen if corrosion damages the heat exchanger. First, it affects suction inside this chamber, leading to less airflow and increased flame rollout. Second, it releases fumes, including carbon monoxide, into your home. Inhaling CO gas can be fatal, so never ignore your carbon monoxide alarms. CO gas can also return to the source of the leak and ignite if a flame is found.

Improper Gas Pressure

Furnaces depend on a precise combination of natural gas and air to produce safe and efficient combustion. Too little pressure is often because of clogged burner orifices. This problem makes the burner flames more likely to roll out. It also produces unwanted condensation in the heat exchanger, accelerating the rate of corrosion.

Conversely, high gas pressure can lead to excessive heat in the furnace, which can cause the soot inside the heat exchanger to combust. Such fires can readily spread to other areas.

How to Prevent Furnace Fires

Based on the various ways a furnace can catch fire, here are the steps you can take to prevent furnace fires:

    • Replace the air filter on a regular basis: Check the filter monthly and change it when it looks dirty or every three months, whichever comes first.
    • Check the furnace flue: Inspect the exterior vent for obstructions and clear out any you find.
    • Don’t store combustible items near the furnace: Things including cardboard boxes, paper, clothing and other combustibles should be kept at a minimum 3 feet away from the furnace and any other heating equipment.
    • Put in a flame rollout switch: This safety device recognizes if a fire or hot exhaust gases are inside your furnace’s burner compartment. If the rollout switch trips, have your furnace inspected as soon as possible to diagnose and repair the problem before it results in a furnace fire.
    • Request annual furnace maintenance: It isn’t always easy to notice if your furnace is working unsafely. Whether you notice warning signs or not, don’t forget furnace maintenance every fall.

Schedule Furnace Services Today

Is it time for your annual tune-up? Do you need help fixing a problem with your furnace? Whatever is happening, Service Experts Heating, Air Conditioning & Plumbing is here for you. Our HVAC experts can inspect, clean and test the system to ensure safe operation. If anything looks out of place, we’ll suggest a repair or a modification, offering you peace of mind that your furnace is unlikely to catch fire. For more info or to schedule furnace maintenance, please contact your local Service Experts Heating, Air Conditioning & Plumbing office today.

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