Can Furnaces Catch Fire?

The return of cold temperatures boosts your reliance on home heating equipment every fall. If your furnace isn’t working correctly, it could become a fire hazard and threaten your family’s safety. 

According to the National Fire Protection Association (NFPA), heating systems like furnaces 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 every year. Space heaters and fireplaces generate the majority of fires concerning heating equipment, but central heaters, like furnaces, are responsible for just about 12% of these blazes. Learn more about the most likely causes of furnace fires and how to avoid them. 

Causes of Furnace Fires

Old furnaces are more vulnerable to safety hazards because they might be manufactured differently and slide 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 biggest risks:  

• A clogged filter can block airflow and force the motor to work more. Sooner or later, the motor can overheat, raising the risk of fire. 
• Dirt can collect around and coat the motor, forcing it to absorb heat, which can trigger a fire. 
• Exposed or damaged wiring can cause the voltage to get too high, increasing the chances of an electrical fire. 
• Overly tight or worn motor bearings can heat up whenever the furnace starts. Without the proper lubrication, the bearings could eventually catch fire. 

Blocked Furnace Flue 

Yard waste, animal nests and other materials can clog the furnace flue, reducing oxygen. This leads to soot buildup and weaker ventilation, limiting efficiency and increasing the risk of flame rollout. Flame rollout is when fire escapes the heat exchanger and burns the parts in your furnace. If this problem continues, your heating equipment can be seriously damaged, and the fire can spread to areas outside the furnace. 

Clogged Heat Exchanger 

The heat exchanger is a sealed combustion chamber where the heat generated by your furnace is exchanged to the air circulating within your home. A heat exchanger clogged up 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 

Numerous problems can happen if corrosion damages the heat exchanger. First, it affects suction within this chamber, leading to less airflow and increased flame rollout. Second, it releases fumes, like 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 lit. 

Improper Gas Pressure 

Furnaces require an exact 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 causes unwanted condensation inside 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 quickly spread to other areas. 

How to Prevent Furnace Fires 

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

• Change the air filter on a regular basis: Check the filter each month and change it when it looks dirty or every three months, whichever comes first. 
• Check the furnace flue: Examine the exterior vent for obstructions and take care of any you find. 
• Don’t store combustible items near the furnace: Things such as cardboard boxes, paper, clothing and other combustibles should be kept more than 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. 

• Request yearly furnace maintenance: It isn’t always easy to recognize 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 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 provide safe operation. If anything doesn’t seem right, we’ll suggest 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.