Can Furnaces Catch Fire?

The return of cold temperatures boosts your dependence on home heating equipment each fall. If your furnace isn’t operating properly, it may develop into a fire hazard and threaten your family’s safety. 

As stated by the National Fire Protection Association (NFPA), heating systems are a major source of home fires, contributing to approximately 50,000 blazes, 500 civilian deaths and more than $1 billion in significant property damage annually. Space heaters and fireplaces generate the majority of fires involving heating equipment, but central heaters, including furnaces, are liable for just about 12% of these blazes. Learn the primary causes of furnace fires and how to minimize them. 

Causes of Furnace Fires

Aging furnaces are more susceptible to safety hazards since they could be configured 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 various ways. Here are the main risks:  

• A clogged filter can restrict airflow and force the motor to work longer. Sooner or later, the motor can overheat, increasing the risk of fire. 
• Dirt can accumulate around and insulate the motor, forcing it to retain heat, which can trigger a fire. 
• Exposed or corroded wiring can cause the voltage to increase too much, increasing the chances of an electrical fire. 
• Exceedingly tight or damaged motor bearings can heat up whenever the furnace runs. Without the proper lubrication, the bearings can eventually light on fire. 

Blocked Furnace Flue 

Yard waste, animal nests and other obstructions can block the furnace flue, lowering oxygen. This leads to soot building up and weaker ventilation, decreasing efficiency and raising the risk of flame rollout. Flame rollout is when fire gets out of the heat exchanger and burns the parts within your furnace. If this problem remains, your heating equipment can be severely damaged, and the fire may even spread to areas outside the furnace. 

Clogged Heat Exchanger 

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

Cracked Heat Exchanger 

Several problems can happen if corrosion breaks the heat exchanger. First, it lowers suction within this chamber, triggering less airflow and increased flame rollout. Second, it emits fumes, including carbon monoxide, into your home. Inhaling CO gas can be fatal, so never dismiss 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 exact mixture of natural gas and air to ensure 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 in the heat exchanger, increasing the rate of corrosion. 

Conversely, high gas pressure can produce excessive heat inside 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 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. 
• Check the furnace flue: Periodically check the exterior vent for obstructions and clear out any you find. 
• Don’t place combustible items close to 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. 
• 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 triggers, have your furnace inspected promptly to diagnose and repair the problem before it results in a furnace fire. 

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

Schedule Furnace Services Today 

Is it time for your yearly 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 pros can inspect, clean and test the system to ensure safe operation. If anything doesn’t seem right, we’ll perform 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.