Can Furnaces Catch Fire?

The return of cold temperatures raises your dependency on home heating equipment each fall. If your furnace isn’t working properly, it may 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, leading to nearly 50,000 blazes, 500 civilian deaths and more than $1 billion in significant property damage annually. Space heaters and fireplaces cause the majority of fires involving heating equipment, but central heaters, such as furnaces, are responsible for about 12% of these blazes. Learn more about the most likely causes of furnace fires and how to minimize them. 

Causes of Furnace Fires

Old furnaces are more susceptible to safety hazards because they may be designed differently and slide 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. 

An Overheated Motor

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

• A clogged filter can restrict airflow and force the motor to work harder. Sooner or later, the motor can overheat, raising the risk of fire. 
• Dirt can gather around and cover up the motor, forcing it to absorb heat, which can cause a fire. 
• Exposed or corroded wiring can cause the voltage to increase too much, increasing the risk of an electrical fire. 
• Overly tight or worn motor bearings can heat up whenever the furnace starts. Without adequate lubrication, the bearings could eventually light on fire. 

Clogged Furnace Flue 

Yard waste, animal nests and other materials can block the furnace flue, lowering oxygen. This causes soot building up and bad ventilation, lowering 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 remains, your heating equipment may be severely damaged, and the fire may even spread to areas outside the furnace. 

Obstructed Heat Exchanger 

The heat exchanger is a restricted combustion chamber where the heat generated by your furnace is moved to the air circulating within your home. A heat exchanger clogged up 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 breaks the heat exchanger. First, it reduces suction in this chamber, resulting in less airflow and increased flame rollout. Second, it releases fumes, like carbon monoxide, into your home. Breathing in CO gas can be lethal, so never dismiss your carbon monoxide alarms. CO gas can also return to the source of the leak and ignite if a flame is lit. 

Inadequate Gas Pressure 

Furnaces depend on an exact combination of natural gas and air to create 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, increasing the rate of corrosion. 

On the other hand, 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 combust, here are the steps you can take to avoid furnace fires: 

• Change the air filter consistently: Check the filter monthly and change it when it appears 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 place combustible items close to the furnace: Things like cardboard boxes, paper, clothing and other combustibles should be kept at least 3 feet away from the furnace and any other heating equipment. 
• Put in 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 produces 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, 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 reason, 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 seems off, we’ll recommend 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.