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Can a furnace explode? | Detailing the warning signs of dangerous furnaces.

Feb 26, 2022 | Central Heating, Furnaces


Can a furnace explode?

Yes, furnaces can explode. The natural gas that serves furnaces is flammable. However, home explosions caused by furnaces are very rare. Modern furnaces have built-in safety features to shut off when something goes amiss.

After 5 or more years of use, weaknesses in your furnace can develop.

Most furnace explosions occur in winter, especially at startup, when a boiler burner is lit up, and there is an increased furnace load.

That’s when weaknesses in your home’s central heating system are put to the test.

How can a furnace explode?

Your furnace burns fuel to produce heat; it releases carbon monoxide.

While a properly maintained furnaces will release carbon monoxide gas through vents, an aging, or poorly serviced furnace can have leak through which carbon monoxide escapes.

This is what happened to one family in Cambridge, Minnesota, after their house exploded on furnace start up.

Furnaces have an ignition source, being the pilot light.

That means any accumulation of any flammable gas puts your furnace and home at risk of explosion.

How dangerous are furnace explosions?

Any gas-powered furnace-related explosions can be fatal.

A natural gas related explosion in Scarborough, Ontario, not only leveled the house, but left 1 dead, and another injured.

Gas furnace explosions can be so powerful that neighboring properties may be hit by debris or receive structural damage from the shock wave.

Warning signs that your gas furnace can explode.

Improper furnace installations

Improper furnace installations are the leading cause of furnace explosions.

In fact, the dangers associated with improper furnace installations are why, in most jurisdictions, it is illegal for anyone without a license to attempt to repair or install an appliance connected to a gas main.

Joints can not be sealed properly. Pressure valves can malfunction, allowing too much pressure to rupture a line. This is often a problem with flexible gas lines. Any botched furnace repair or installation job can mean toxic gases entering the house and a risk of combustion.

Fuel or gas smell

If you notice fuel, odor, or egg smell coming from your furnace or boiler room, it can be a serious issue. You should immediately evacuate the home or building. Following evacuation, have a certified HVAC technician inspect your central heating systems and gas connections. This is not a job you should attempt to DIY fix yourself!

The flame of the burner is yellow rather than blue

Your furnace could leak carbon monoxide if it has a yellow burner flame(also called pilot light) instead of a blue one.

The invisibility, odorlessness, and flammability of carbon monoxide make it a very dangerous gas.

If your chimney has no draft upward, carbon monoxide particles may accumulate around your furnace.

If you suspect carbon monoxide leaks, shut off the gas, get everyone outside, and immediately contact a professional furnace technician or licensed gas fitter.

Your furnace is old

Many old furnaces run on oil or gas.

While many new furnaces do as well, comparatively, new furnaces have more advanced safety features, such as flame rollout sensors, flameproofing sensors, high-temperature limit control, flue exhaust pressure sensors, and fan limit sensors.

Without proper ventilation, old furnaces are a fire hazard.

Old furnaces can also develop cracks, leaking gas into the air, allowing carbon monoxide into the house instead of air.

It is also wise to keep any flammable materials away from your old furnace, as this increases the chance of a fire and subsequent furnace explosion.

Digging in the local area

When furnace-related explosions do happen, it’s usually because someone is digging on land nearby and cuts a gas line.

Leaking gas from cut pipelines can saturate the soil around homes and migrate into them through drainage systems or other service lines.

Fatal house explosions can be caused by odorless gas seeping from a cut-off pipeline into the house through French drains or sump pits.

Any contractor digging in the area needs to have municipal approval to do so.

Gas-powered furnaces, combined with gas leaks from external underground sources, can be a dangerous combination.

The furnace is the ignition source in these cases.

Constantly having to adjust the thermostat

If you are not getting the heat out of your furnace you desire, this could be a simple fix or thermostat adjustment. However, it could also pose more serious concerns that should be investigated by a licensed furnace technician.

Poor efficiency or operation

Get your furnace inspected if it is struggling to maintain the temperature in your home or resulting in hiked up energy or gas costs.

A poorly operated or inefficient furnace is a telltale sign that some components in your furnace may need replacement.

Any component on a furnace, whether related to its basic function or a safety feature, is incredibly important to have inspected for its operation.

Ideally, you will want to have your furnace inspected before start up in the winter.

How can you prevent furnace explosions?

Now, if you’ve been asking yourself, “Can a furnace explode?” it is clear the answer is yes.

Here are some simple tips for furnace explosion prevention:

  • Replace furnaces over 10 years in age.
  • Keep up with regular furnace service.
  • Check gas connections, fittings, lines, and exhaust ducts.
  • Call the local gas company about underground lines if you are digging in the area.
  • Only trust the services of a licensed gas fitting expert.
  • Do not perform DIY repairs on a furnace.
  • Keep your CO(carbon monoxide) detector powered and operational.

Overall, if you’re uncomfortable assessing your furnace’s health, call a professional.

Thanks for reading. If you found this post useful, share it with others.



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