Can Furnaces Catch Fire?

The return of low temperatures raises your dependency on home heating equipment each fall. If your furnace isn’t operating correctly, it might become a fire hazard and threaten your family’s safety. 

According to the National Fire Protection Association (NFPA), heating systems are a top source of home fires, leading to nearly 50,000 blazes, 500 civilian deaths and more than $1 billion in direct property damage each year. Space heaters and fireplaces start the majority of fires involving heating equipment, but central heaters, like furnaces, are responsible 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 exposed to safety problems because they may be designed differently and settle into disrepair over the years. Nevertheless, whether your furnace is more than a decade old or brand new, you should be aware of these causes of furnace fires. 

Overheating Motor

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

• A clogged filter can restrict airflow and cause the motor to work more. At some point, the motor can overheat, increasing the risk of fire. 
• Dirt can gather around and coat 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. 
• Exceedingly tight or worn motor bearings can heat up as the furnace is on. Without the proper lubrication, the bearings can eventually catch fire. 

Clogged Furnace Flue 

Yard debris, animal nests and other obstructions can block the furnace flue, lowering oxygen. This leads to soot accumulation and bad ventilation, decreasing efficiency and raising the risk of flame rollout. Flame rollout is when fire escapes the heat exchanger and burns the parts within your furnace. If this problem persists, your heating equipment could be seriously damaged, and the fire may even spread to areas outside the furnace. 

Obstructed Heat Exchanger 

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

Cracked Heat Exchanger 

Several 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 emits fumes, like carbon monoxide, into your home. Inhaling CO gas can be deadly, so never dismiss your carbon monoxide alarms. CO gas can also return to the source of the leak and ignite if a flame is found. 

Inadequate Gas Pressure 

Furnaces require a precise combination of natural gas and air to generate 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 leads to unwanted condensation within the heat exchanger, accelerating the rate of corrosion. 

Conversely, high gas pressure can lead to excessive heat within the furnace, which can cause the soot inside the heat exchanger to burn. Such fires can quickly spread to other areas. 

How to Prevent Furnace Fires 

Based on the listed ways a furnace can light on fire, here are the steps you can take to avoid furnace fires: 

• Replace the air filter regularly: Check the filter once a month and change it when it appears dirty or every three months, whichever comes first. 
• Check the furnace flue: Periodically check the exterior vent for obstructions and take care of any you find. 
• Don’t store combustible items around the furnace: Things including cardboard boxes, paper, clothing and other combustibles should be kept at least 3 feet away from the furnace and all other heating equipment. 
• Install a flame rollout switch: This safety component 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 results in a furnace fire. 

• Request yearly furnace maintenance: It isn’t always easy to tell if your furnace is performing unsafely. Whether you notice warning signs or not, prioritize furnace maintenance every fall. 

Schedule Furnace Services Today 

Is it time for your annual tune-up? Do you need help taking care of a problem with your furnace? Whatever the reason, Service Experts Heating, Air Conditioning & Plumbing is here for you. Our HVAC professionals can inspect, clean and test the system to provide safe operation. If anything doesn’t seem right, we’ll recommend a repair or a modification, providing 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.