Can Furnaces Catch Fire

The return of low temperatures boosts your dependency on home heating equipment every fall. If your furnace isn’t functioning correctly, it could develop into a fire hazard and jeopardize your family’s safety.

As reported by the National Fire Protection Association (NFPA), heating systems are a leading factor of home fires, causing nearly 50,000 blazes, 500 civilian deaths and more than $1 billion in direct property damage each year. Space heaters and fireplaces start most of the fires affecting heating equipment, but central heaters, such as furnaces, are liable for about 12% of these blazes. Find out more about the primary causes of furnace fires and how to avoid them.

Causes of Furnace Fires

Older furnaces are more susceptible to safety hazards since they could be manufactured differently and slide into disrepair over the years. That being said, whether your furnace is more than a decade old or brand new, you should be familiar with these causes of furnace fires.

Overheated Motor

A furnace motor can overheat in different ways. Here are the most common risks: 
  • A clogged filter can impede airflow and force the motor to work harder. At some point, the motor might overheat, elevating the risk of fire.
  • Dirt can accumulate around and insulate the motor, forcing it to absorb heat, which can trigger a fire.
  • Exposed or deteriorated wiring can cause the voltage to increase too much, increasing the likelihood of an electrical fire.
  • Excessively tight or worn motor bearings can heat up as the furnace runs. Without the appropriate lubrication, the bearings may eventually light on fire.

Obstructed Furnace Flue

Yard waste, animal nests and other obstructions can obstruct the furnace flue, reducing oxygen. This causes soot building up and improper ventilation, decreasing efficiency and increasing the risk of flame rollout. Flame rollout is when fire reaches past the heat exchanger and burns the parts within your furnace. If this problem remains, your heating equipment could be badly damaged, and the fire may even spread to areas outside the furnace.

Clogged Heat Exchanger

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

Cracked Heat Exchanger

Various problems can take place if corrosion damages the heat exchanger. First, it lowers suction within this chamber, resulting in less airflow and increased flame rollout. Second, it emits fumes, such as carbon monoxide, into your home. Breathing in CO gas can be lethal, so never neglect your carbon monoxide alarms. CO gas can also flash back to the source of the leak and ignite if a flame is present.

Improper Gas Pressure

Furnaces need an accurate mixture of natural gas and air to ensure safe and efficient combustion. Too little pressure is often the result of clogged burner orifices. This problem makes the burner flames more likely to roll out. It also produces unwanted condensation within the heat exchanger, increasing the rate of corrosion.
Conversely, high gas pressure can create excessive heat within 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:

  • Change the air filter consistently: Check the filter once a month and change it when it appears dirty or every three months, whichever comes first.
  • Keep an eye on the furnace flue: Inspect the exterior vent for obstructions and remove any you find.
  • Don’t keep combustible items around the furnace: Things such as cardboard boxes, paper, clothing and other combustibles should be kept at least 3 feet away from the furnace and any other heating equipment.
  • Add 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 promptly to diagnose and repair the problem before it produces a furnace fire.
  • Schedule yearly furnace maintenance: It isn’t always easy to tell if your furnace is operating 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 resolving a problem with your furnace? Whatever the reason, Service Experts Heating & Air Conditioning is here for you. Our HVAC experts can inspect, clean and test the system to guarantee safe operation. If anything doesn't seem right, we’ll suggest a repair or a modification, offering you peace of mind that your furnace is unlikely to catch fire. For more information or to schedule furnace maintenance, please contact your local Service Experts Heating & Air Conditioning office today.