The return of cold temperatures boosts your reliance on home heating equipment every fall. If your furnace isn’t operating correctly, it may develop into a fire hazard and threaten your family’s safety.
As stated by the National Fire Protection Association (NFPA), heating systems are a major cause of home fires, contributing to nearly 50,000 blazes, 500 civilian deaths and more than $1 billion in direct property damage annually. Space heaters and fireplaces cause the majority of fires concerning heating equipment, but central heaters, including furnaces, are liable for just about 12% of these blazes. Learn the primary causes of furnace fires and how to prevent them.
Causes of Furnace Fires
Aging furnaces are more susceptible to safety concerns because they could be designed differently and slide into disrepair over the years. That being said, whether your furnace is more than a decade old or brand new, you should be familiar with these causes of furnace fires.
An Overheated Motor
A furnace motor can overheat in several ways. Here are the biggest risks:
- A clogged filter can block airflow and cause the motor to work longer. Eventually, the motor may overheat, elevating the risk of fire.
- Dirt can collect around and insulate the motor, forcing it to absorb heat, which can cause a fire.
- Exposed or corroded wiring can cause the voltage to get too high, increasing the risk of an electrical fire.
- Overly 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 obstructions can block the furnace flue, reducing oxygen. This results in soot accumulation and weaker 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 can be badly 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 produced by your furnace transfers to the air circulating within your home. A heat exchanger clogged up 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
Numerous problems can take place if corrosion breaks the heat exchanger. First, it affects suction inside this chamber, triggering less airflow and increased flame rollout. Second, it emits fumes, including 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 found.
Improper Gas Pressure
Furnaces need a precise combination of natural gas and air to ensure 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 causes unwanted condensation within 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 burn. Such fires can easily 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 on a regular basis: Check the filter monthly and change it when it seems dirty or every three months, whichever comes first.
- Keep an eye on the furnace flue: Examine the exterior vent for obstructions and take care of any you find.
- Don’t keep combustible items close to the furnace: Things such as cardboard boxes, paper, clothing and other combustibles should be kept more than 3 feet away from the furnace and all 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 triggers, have your furnace inspected right away to diagnose and repair the problem before it produces a furnace fire.
- Request annual furnace maintenance: It isn’t always easy to notice if your furnace is performing 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 fixing a problem with your furnace? Whatever the reason, Stevenson Service Experts is here for you. Our HVAC professionals can inspect, clean and test the system to guarantee safe operation. If anything seems off, we’ll suggest 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 Stevenson Service Experts office