Can Furnaces Catch Fire?

The return of cooler temperatures boosts your reliance on home heating equipment each fall. If your furnace isn’t functioning 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 top cause of home fires, leading to almost 50,000 blazes, 500 civilian deaths and more than $1 billion in significant property damage every year. Space heaters and fireplaces cause the majority of fires involving heating equipment, but central heaters, such as furnaces, are responsible for around 12% of these blazes. Learn more about the primary causes of furnace fires and how to prevent them. 

Causes of Furnace Fires

Older furnaces are more susceptible to safety problems because they could be manufactured differently and fall into disrepair over 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 different ways. Here are the main risks:  

• A clogged filter can impede airflow and cause the motor to work more. Sooner or later, the motor can overheat, raising the risk of fire. 
• Dirt can gather around and insulate the motor, forcing it to hold heat, which can cause a fire. 
• Exposed or damaged wiring can cause the voltage to increase too much, increasing the risk of an electrical fire. 
• Exceedingly tight or damaged motor bearings can heat up when the furnace runs. Without the proper lubrication, the bearings may eventually light on fire. 

Obstructed Furnace Flue 

Yard waste, animal nests and other materials can block the furnace flue, lowering oxygen. This causes soot buildup and improper 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 can spread to areas outside the furnace. 

Obstructed Heat Exchanger 

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

Several problems can take place if corrosion breaks the heat exchanger. First, it reduces suction within this chamber, resulting in less airflow and increased flame rollout. Second, it emits fumes, like carbon monoxide, into your home. Breathing CO gas can be fatal, so never dismiss your carbon monoxide alarms. CO gas can also return to the source of the leak and ignite if a flame is present. 

Inadequate Gas Pressure 

Furnaces need an exact mixture of natural gas and air to produce 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 within the heat exchanger, increasing 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 combust. Such fires can quickly spread to other areas. 

How to Prevent Furnace Fires 

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

• Replace the air filter on a regular basis: Check the filter monthly 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 take care of any you find. 
• Don’t place combustible items close to the furnace: Things such as cardboard boxes, paper, clothing and other combustibles should be kept at a minimum 3 feet away from the furnace and any other heating equipment. 
• Put in a flame rollout switch: This safety system detects if a fire or hot exhaust gases are inside your furnace’s burner compartment. If the rollout switch trips, have your furnace inspected as soon as possible to diagnose and repair the problem before it causes a furnace fire. 

• Schedule annual furnace maintenance: It isn’t always easy to notice 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 the reason, Service Experts Heating, Air Conditioning & Plumbing is here for you. Our HVAC experts can inspect, clean and test the system to provide safe operation. If anything looks out of place, we’ll perform a repair or a modification, offering you peace of mind that your furnace is unlikely to catch fire. For more info or to schedule furnace maintenance, please contact your local Service Experts Heating, Air Conditioning & Plumbing office today.