The return of cooler temperatures boosts your dependence on home heating equipment in the fall. If your furnace isn’t operating correctly, it could become a fire hazard and endanger your family’s safety.
According to the National Fire Protection Association (NFPA), heating equipment is a leading cause of home fires, contributing to almost 50,000 blazes, 500 civilian deaths and more than $1 billion in significant property damage annually. Space heaters and fireplaces cause most of the fires involving heating equipment, but central heaters, including furnaces, are responsible for around 12% of these blazes. Learn more about the primary causes of furnace fires and how to avoid them.
Causes of Furnace Fires
Older furnaces are more exposed to safety concerns as they could be manufactured differently and settle into disrepair through the years. Still, whether your furnace is more than a decade old or brand new, you should know about these causes of furnace fires.
An Overheated Motor
A furnace motor can overheat in various ways. Here are the main risks:
- A clogged filter can restrict airflow and cause the motor to work more. Sooner or later, the motor can overheat, raising the risk of fire.
- Dirt can accumulate around and coat the motor, forcing it to absorb heat, which can lead to a fire.
- Exposed or corroded wiring can cause the voltage to increase too much, increasing the chances of an electrical fire.
- Excessively tight or worn motor bearings can heat up when the furnace runs. Without adequate lubrication, the bearings can eventually light on fire.
Clogged Furnace Flue
Yard waste, animal nests and other obstructions can clog the furnace flue, lowering oxygen. This results in soot building up and weaker ventilation, lowering efficiency and increasing the risk of flame rollout. Flame rollout is when fire gets out of the heat exchanger and burns the parts inside your furnace. If this problem remains, your heating equipment may be seriously 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 transfers to the air circulating throughout your home. A heat exchanger blocked 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 happen if corrosion cracks the heat exchanger. First, it lowers suction in this chamber, resulting in less airflow and increased flame rollout. Second, it releases fumes, such as carbon monoxide, into your home. Inhaling CO gas can be lethal, 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 present.
Improper Gas Pressure
Furnaces need 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 leads to unwanted condensation in the heat exchanger, accelerating the rate of corrosion.
Conversely, high gas pressure can produce excessive heat within the furnace, which can cause the soot inside the heat exchanger to ignite. 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:
- Replace 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: Inspect the exterior vent for obstructions and take care of any you find.
- Don’t store combustible items around 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.
- Add a flame rollout switch: This safety device detects 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 results in a furnace fire.
- Request yearly furnace maintenance: It isn’t always easy to recognize if your furnace is performing unsafely. Whether you notice warning signs or not, prioritize 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 is happening, Service Experts Heating & Air Conditioning is here for you. Our HVAC professionals can inspect, clean and test the system to provide safe operation. If anything doesn't seem right, we’ll recommend a repair or a modification, offering you peace of mind that your furnace is unlikely to catch fire. For more details or to schedule furnace maintenance, please contact your local Service Experts Heating & Air Conditioning office