Can Furnaces Catch Fire?

The return of low temperatures boosts your dependence on home heating equipment each fall. If your furnace isn’t operating correctly, it might develop into a fire hazard and jeopardize your family’s safety. 

According to the National Fire Protection Association (NFPA), heating equipment is a major source of home fires, leading to nearly 50,000 blazes, 500 civilian deaths and more than $1 billion in direct property damage every year. Space heaters and fireplaces generate most of the fires affecting heating equipment, but central heaters, like furnaces, are responsible for just about 12% of these blazes. Learn the leading causes of furnace fires and how to avoid them. 

Causes of Furnace Fires

Aging furnaces are more exposed to safety concerns as they may be designed differently and fall into disrepair through the years. That being said, whether your furnace is more than a decade old or brand new, you should be aware of these causes of furnace fires. 

An Overheated Motor

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

• A clogged filter can impede airflow and cause the motor to work more. Eventually, the motor might overheat, increasing the risk of fire. 
• Dirt can gather 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 get too high, increasing the likelihood of an electrical fire. 
• Overly tight or worn motor bearings can heat up whenever the furnace is on. Without adequate lubrication, the bearings may eventually catch fire. 

Blocked Furnace Flue 

Yard debris, animal nests and other obstructions can obstruct the furnace flue, restricting oxygen. This causes soot buildup and improper ventilation, lowering efficiency and increasing the risk of flame rollout. Flame rollout is when fire reaches past the heat exchanger and burns the parts in your furnace. If this problem persists, your heating equipment may be seriously 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 produced by your furnace transfers 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 higher risk of flame rollout. 

Cracked Heat Exchanger 

Numerous problems can take place if corrosion cracks the heat exchanger. First, it lowers suction inside this chamber, resulting in less airflow and increased flame rollout. Second, it releases fumes, including carbon monoxide, into your home. Breathing CO gas can be fatal, so never ignore 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 need an accurate 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 produces unwanted condensation in the heat exchanger, accelerating the rate of corrosion. 

On the other hand, high gas pressure can produce excessive heat in 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 various 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 appears dirty or every three months, whichever comes first. 
• Keep an eye on the furnace flue: Periodically check the exterior vent for obstructions and remove any you find. 
• Don’t place combustible items close to the furnace: Things like cardboard boxes, paper, clothing and other combustibles should be kept more than 3 feet away from the furnace and any other heating equipment. 
• Install 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 triggers, have your furnace inspected right away to diagnose and repair the problem before it produces a furnace fire. 

• Request 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 yearly tune-up? Do you need help resolving a problem with your furnace? Whatever the case, Service Experts Heating, Air Conditioning & Plumbing is here for you. Our HVAC pros 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 information or to schedule furnace maintenance, please contact your local Service Experts Heating, Air Conditioning & Plumbing office today.