What can cause a furnace to explode?

Author: Mr. Gino Strosin  |  Last update: Wednesday, April 9, 2025

A furnace explosion is usually the result of ignition and instantaneous combustion of highly flammable gas, vapor, or dust that has accumulated in a boiler. The effect of the force from the explosion is often much greater than the boiler combustion chamber can withstand.

How common is a furnace explosion?

Although it is possible for a gas furnace to either catch fire or explode, it's highly unlikely. If there is a danger of this happening, the furnace will usually simply shut off—as it's designed to. Regular maintenance will further reduce this already unlikely event.

What makes a furnace pop?

Homeowners often notice a popping sound when the furnace begins a cycle. This is due to warm air that hits the cold metal of the ducts, which causes expansion and produces that noise. When the popping noise is louder, your gas furnace's burners may be dirty.

Why would a gas heater explode?

Leaking pipes, faulty appliances, a defective valve or an incorrectly connected gas cooker can cause gas to escape into the room air and quickly reach critical limit values. Even small amounts of gas are enough to cause an explosion.

What would cause a furnace to catch fire?

Yard debris, animal nests and other obstructions can block the furnace flue, restricting oxygen. This leads to soot buildup and bad ventilation, decreasing 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.

Explosions During Furnace Ignition - Symptom of Bad Heat Exchanger

Why did my furnace explode?

A furnace explosion is usually the result of ignition and instantaneous combustion of highly flammable gas, vapor, or dust that has accumulated in a boiler. The effect of the force from the explosion is often much greater than the boiler combustion chamber can withstand.

What is the most common furnace failure?

One of the most common furnace problems is a malfunctioning thermostat. A sure sign your thermostat isn't working properly is if your fan is constantly running. This will cause your thermostat battery to run, and cause your furnace to work inefficiently.

What are the symptoms of gas heater poisoning?

Key points about carbon monoxide poisoning

Most CO exposures happen in the winter. A common source is unvented space heaters. Symptoms of CO poisoning include headache, dizziness, weakness, nausea and vomiting, rapid heartbeat, shortness of breath, seizures, chest pain, disorientation, and loss of consciousness.

Why did my heater explode?

If there is the electric heating element explosion, it's very likely that it's getting very damp. Once the magnesium oxide powder is severely affected by the electric heating, the water evaporates rapidly, and the metal tube may be blasted when the pressure is high.

How much is a new furnace?

Ask twenty professional HVAC contractors the question, “How Much Does A New Furnace Cost?” and you'll probably get the same answer... “It depends.” On average, the cost of a new furnace can range from $2,000 - $14,2001. However, factors like furnace efficiency, type, size, and much more can impact this range.

Why is my furnace making an explosion noise?

If your furnace makes a booming sound when it starts up, this is usually due to what HVAC specialists call “delayed ignition”. Unfortunately, delayed ignition should never be ignored as it can cause severe damage to your furnace and even your family if left unaddressed.

What causes a furnace fuse to pop?

In an electric furnace, if the thermostat wire touches the metal frame of the furnace, it can cause a blown fuse. When the wire touches the metal frame, it can deliver a higher voltage than the wires are meant to handle. This will cause a fuse to blow.

Is it normal for a furnace to pop?

Banging or Popping Sounds

Banging and popping sounds in a furnace are usually related to the natural expansion and contraction of the metal ductwork. As the furnace heats up, the ducts expand, and as it cools down, they contract.

What is the typical lifespan of a furnace?

The Average Furnace Lifespan

A well-maintained furnace can last at least 15 to 20 years, but completing annual maintenance and being diligent with repairs can extend its life even longer.

What are the odds of a house exploding?

buildings are presented. concluded that in the USA the probability of occurrence of an explosion capable of causing significant structural damage could be 2.2 per million housing units per year.

Why does my furnace keep exploding?

Dirty heating equipment can cause a problem called "delayed ignition" where there is a small explosion within the combustion chamber. Preventative heating maintenance is the way to prevent the furnace sound of "tick tick BOOM." Get that heater repaired and continue with routine inspection and cleanings.

What causes a gas heater to explode?

Below are a few of the major causes of gas explosion: Improper use of gas furnace, stove, or appliance, including leaking due to hooking up gas lines incorrectly. Old, worn-out, rusty gas lines coming from the street into your home.

What happens if a heater explodes?

The water from the explosion is scalding hot and can leave you with burns. Finally, the water heater is made of metal, which can turn into dangerous shrapnel in an explosion. Any one of these things would be dangerous on its own; together, they are an absolute disaster. The explosion also causes property damage.

What are two warning signs of carbon monoxide poisoning?

The most common symptoms of CO poisoning are headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion. CO symptoms are often described as “flu-like.” If you breathe in a lot of CO, it can make you pass out or kill you.

Is my gas furnace making me sick?

Constantly breathing extremely warm, dry air that may contain fungi, mold and mildew from the vents can affect your skin, nose, throat and eyes. Breathing these air particulates and smelling the bacteria may cause sneezing, congestion headaches, coughing and drying out your eyes, nose and throat.

How do I know if my gas heater is safe?

Check for changes in how your gas heater operates. For example if the flame changes from its usual colour. If there is any change, you must get a qualified gasfitter to inspect your gas heater and check it for CO leakage. If your heater is old, or hasn't been serviced for several years, consider replacing it.

How common are furnace explosions?

Highly UNLIKELY! Furnaces and boilers have multiple safeties to prevent an explosion.

What usually breaks on a gas furnace?

The blower motor circulates the heated air throughout your home. If the blower motor fails, you won't get warm air from your furnace. Common causes of blower motor failure include worn-out bearings, a faulty capacitor, or a malfunctioning control board.

What is the most expensive repair on a furnace?

A heat exchanger replacement is often one of the most costly repairs in a furnace, and the expense can sometimes rival that of installing a new furnace. Typical replacement costs vary widely but can easily reach several thousand dollars, especially if labor costs are factored in.

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