Can Furnaces Catch Fire?

The return of low temperatures boosts your dependency on home heating equipment every fall. If your furnace isn’t working properly, it may develop into a fire hazard and threaten your family’s safety. 

As reported by the National Fire Protection Association (NFPA), heating systems are a top source of home fires, causing nearly 50,000 blazes, 500 civilian deaths and more than $1 billion in direct property damage annually. Space heaters and fireplaces cause most of the fires involving 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 minimize them. 

Causes of Furnace Fires

Old furnaces are more vulnerable to safety concerns because they might be designed 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 various ways. Here are the main risks:  

  • A clogged filter can restrict airflow and force the motor to work harder. Eventually, the motor can overheat, raising the risk of fire. 
  • Dirt can accumulate around and cover up the motor, forcing it to retain heat, which can trigger a fire. 
  • Exposed or damaged wiring can cause the voltage to get too high, increasing the risk of an electrical fire. 
  • Excessively tight or damaged motor bearings can heat up when the furnace is on. Without adequate lubrication, the bearings can eventually catch fire. 

Blocked Furnace Flue 

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

Obstructed Heat Exchanger 

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

Cracked Heat Exchanger 

Various problems occur if corrosion cracks the heat exchanger. First, it lowers suction in this chamber, triggering less airflow and increased flame rollout. Second, it releases fumes, including carbon monoxide, into your home. Breathing in CO gas can be fatal, so never neglect your carbon monoxide alarms. CO gas can also flash back to the source of the leak and ignite if a flame is lit. 

Inadequate Gas Pressure 

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

How to Prevent Furnace Fires 

Based on the various ways a furnace can combust, 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: Inspect the exterior vent for obstructions and take care of any you find. 
  • Don’t store 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. 
  • Install 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. 
  • Schedule yearly furnace maintenance: It isn’t always easy to notice if your furnace is working unsafely. Whether you notice warning signs or not, remember 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 the reason, Service Experts Heating, Air Conditioning & Plumbing is here for you. Our HVAC professionals can inspect, clean and test the system to guarantee 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 information or to schedule furnace maintenance, please contact your local Service Experts Heating, Air Conditioning & Plumbing office today. 

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