Can Furnaces Catch Fire?

The return of cooler temperatures increases your dependency on home heating equipment every fall. If your furnace isn’t operating properly, it may develop into a fire hazard and endanger your family’s safety.

As reported by the National Fire Protection Association (NFPA), heating equipment is a leading factor of home fires, contributing to almost 50,000 blazes, 500 civilian deaths and more than $1 billion in direct property damage every year. Space heaters and fireplaces start most of the fires involving heating equipment, but central heaters, including furnaces, are responsible for about 12% of these blazes. Learn more about the most likely causes of furnace fires and how to prevent them.

Causes of Furnace Fires

Older furnaces are more exposed to safety hazards because they might be designed differently and fall into disrepair through the years. Nevertheless, whether your furnace is more than a decade old or brand new, you should know about these causes of furnace fires.

Overheated Motor

A furnace motor can overheat in several ways. Here are the main risks:

• • A clogged filter can restrict airflow and cause the motor to work more. Eventually, the motor can overheat, increasing the risk of fire.

• • Dirt can collect around and cover up the motor, forcing it to hold heat, which can trigger a fire.

• • Exposed or corroded wiring can cause the voltage to elevate, increasing the risk of an electrical fire.

• • Overly tight or worn motor bearings can heat up when the furnace is on. Without adequate lubrication, the bearings could eventually light on fire.

Clogged Furnace Flue

Yard waste, animal nests and other materials can obstruct the furnace flue, reducing oxygen. This results in soot building up and bad ventilation, decreasing efficiency and increasing the risk of flame rollout. Flame rollout is when fire escapes the heat exchanger and burns the parts within your furnace. If this problem continues, your heating equipment could be severely damaged, and the fire can spread to areas outside the furnace.

Clogged Heat Exchanger

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

Cracked Heat Exchanger

Numerous problems can take place if corrosion cracks the heat exchanger. First, it affects suction in this chamber, triggering less airflow and increased flame rollout. Second, it produces fumes, such as carbon monoxide, into your home. Inhaling CO gas can be fatal, so never neglect 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 require a precise combination 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 leads to unwanted condensation inside the heat exchanger, increasing the rate of corrosion.

On the other hand, high gas pressure can lead to excessive heat within the furnace, which can cause the soot inside the heat exchanger to ignite. Such fires can readily spread to other areas.

How to Prevent Furnace Fires

Based on the various ways a furnace can combust, here are the steps you can take to avoid furnace fires:

• • Replace the air filter on a regular basis: Check the filter once a month and change it when it seems dirty or every three months, whichever comes first.

• • Keep an eye on the furnace flue: Periodically check the exterior vent for obstructions and clear out any you find.

• • Don’t store combustible items close to the furnace: Things including cardboard boxes, paper, clothing and other combustibles should be kept at least 3 feet away from the furnace and any other heating equipment.

• • Put in a flame rollout switch: This safety system 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 annual furnace maintenance: It isn’t always easy to tell if your furnace is performing unsafely. Whether you notice warning signs or not, remember 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 the case, Service Experts Heating, Air Conditioning & Plumbing 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 recommend a repair or a modification, giving you peace of mind that your furnace is unlikely to catch fire. For more details or to schedule furnace maintenance, please contact your local Service Experts Heating, Air Conditioning & Plumbing office today.