Can A Boiler Explode? (Here Are Some Telltale Signs)

Upgraded Home Team
by Upgraded Home Team

Boilers play an important role in any home. These units work by heating water and the house with steam. The steam travels through the house in pipes and radiators. Boilers are expensive to install, but have a long lifespan and are energy efficient.

Boilers can certainly explode due to a build-up of pressure or mechanical failure caused by deterioration of the boiler. If your boiler or the water smells like rotten eggs, your water is brown, or the pipes are making a pinging noise, these are signs your boiler may be at risk of exploding.

Boiler explosions are, unfortunately, more common than most think. Therefore, we share the telltale signs your boiler is at risk of exploding, and what exactly you need to do to keep this from happening.

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What Is A Boiler?

A boiler is a part of a home’s radiant heating system. This appliances’ job is to convert water into steam, which is then distributed through pipes and radiators to warm a space. The water is heated by either a gas or electric heat source.

Boilers are generally found in the basement of a home and are very common in older homes and colder climates. With boilers being centrally located and possessing the ability to evenly spread heat throughout a home, they are a key component in a home’s central heating system.

Home’s with steam or hot water radiators will be heated by boilers. On the other hand, if your property has air registers in your floors, walls, or ceilings, you likely have a furnace instead.

Rather than circulating steam through radiators, furnaces push warm air into each room to raise the indoor temperature.

What Is A Boiler Explosion?

A boiler explosion is described as the “catastrophic failure” of a boiler. Normally, there are two types of boiler explosions: a furnace’s fuel or air explosion and the failure of the pressure of the steam and watersides. In most cases, the following situations are what will cause a boiler to explode:

  • Too high pressure
  • Overheating
  • Weak outer shell or other boiler components

Put simply, a boiler explodes when the pressure is too high or it is simply not strong enough to withstand the pressure that it is designed to take.

On the other hand, fire explosions are defined as the air or fuel explosion of a furnace. These generally occur as a result of a burner flameout.

The buildup of fuel and oil fumes inside the combustion chamber can cause an explosion and a fuel explosion in the firebox will result in damage to the interior shell and tubes of the boiler. This, in turn, can lead to boiler failure or even explosion.

How Do You Know If Your Boiler Is Going To Explode?

There are some telltale signs that something is wrong with your boiler. If you notice these signs, something is wrong. Take action to prevent your boiler from exploding.

  • The boiler smells like rotten eggs. There is probably a gas leak if your boiler smells like sulfur or rotten eggs. This is dangerous and can cause an explosion!
  • Your water smells like rotten eggs. This is still a problem – but less dangerous. Microbes in the tank usually cause the sulfur smell in the water. Left
  • Your water is brown. Rust or sediment is building up in your pipes. This can lead to reduced flow, causing an explosion.
  • The pipes are pinging. The pinging noise is also caused by rust or sediment in the pipes. It can also sound like banging or popping. The sediment can build up and cause an explosion.

How To Prevent An Explosion

How Do You Stop A Boiler From Exploding?

First, make sure that anyone in your home is safe. Boiler explosions can be dangerous.

  • Turn both the boiler and gas source off if the boiler smells like rotten eggs. Seek professional help to fix it before you turn it back on.
  • Replace the anode rod if your water smells like rotten eggs. Don’t put this off, get it fixed quickly.
  • Clean the boiler and pipes if your water is brown or the pipes are pinging. Make sure you turn the system off first. Scrub all of the tubes and clean the heat exchanger. You can clean it yourself or hire someone.

Causes Of Boiler Explosions

Boiler explosions used to be far more common, and they can still explode for several reasons. If you think about it, a boiler is a perfect scenario for an explosion. There is a lot of hot water, heat, and pressure in a small area. Heat is energy, and a small malfunction could create excess energy.

Too Much Pressure

The most common reason for a boiler to explode is too much pressure. Excess energy needs to go somewhere, and the boiler explodes. Newer boilers are designed to withstand greater amounts of pressure than older boilers were capable of.

Boilers can withstand up to 20 PSI. For a little perspective, at sea level, there is 14.7 PSI from the earth’s atmosphere. It takes a lot of pressure to create an explosion. But, if the valves are set too high the boiler can explode because of the excess pressure or heat.

Gas Leak

A gas leak is another reason a boiler can explode. Gas leaks explosions are extremely dangerous because they’re often accompanied by fire. The source of the gas leak is often the container holding the gas but could also be caused by the connection.

System Malfunctions

System malfunctions or weaknesses are a common cause of boiler explosions. It could be the pressure relief valve or corrosion on the boilerplate. If the water level gets too low, the boiler can explode.

Boilers have pressure relief valves that are a safety system and relieve pressure if it builds up too high. Most boilers have two or three of these valves to prevent explosions if the primary valve fails.

Routine safety checks and maintenance will identify and replace any faulty valves. The safety valve malfunction is unlikely to cause a boiler explosion.

The Crown Sheet Buckles

Pressure from the boiler prevents the water that is covering the crown sheet from boiling. But, the crown sheet can buckle if there isn’t enough water covering it. If the crown sheet buckles the pressure builds up and creates an explosion.

Strategies For Keeping Your Boiler Functional

Boiler explosions are rare, but you don’t want one in your home. The best strategy is to avoid an explosion by keeping your boiler functional.

There are several steps that can be taken to avoid a boiler explosion in your home:

  • Conduct routine maintenance checks on your boiler. Hire a professional if this isn’t something you’re comfortable doing. Make sure there isn’t any sediment building up in the pipes.
  • Invest in updates to your boiler every few years. Boilers are heavy-use items, and therefore need to be rebuilt to maintain full functionality. Local HVAC professionals are qualified to service and update boilers. Check and replace valves and rods.
  • Keep the pressure level in the boiler set below the maximum level of the boiler. This means the system is not operating at full capacity. Most boilers should be set between 1 and 1.5 bar – with the optimal pressure level of 1.3 bar. The gauge should always be in the green section.
  • Set the pressure relief valve at a lower pressure level too. This will ensure that pressure is relieved below the maximum capacity of the boiler.
  • Consider turning your boiler off at night. This is an option that some homeowners choose in the spring or fall. In extreme cold, it is not safe or practical. Turning the boiler off overnight is less efficient, but offers peace of mind for some homeowners.

Related Questions

How long does a boiler last?

A boiler will last between 15 and 20 years before it needs to be replaced. The life expectancy of a boiler depends on the amount of use, care and maintenance, and quality. Maintenance is necessary every few years to avoid an explosion.


Can my boiler cause carbon monoxide poisoning?

Yes, boilers can be a source of carbon monoxide poisoning. This only happens if the boiler is not operating correctly or parts of the system are blocked. Carbon monoxide poisoning from boilers can easily be avoided through routine inspections.You want to make sure that there are no leaks, blocks, or operating issues with the boiler during the inspection. All homes should have a carbon monoxide tester on each floor, including the basement. Garages that are attached to the home should also have a carbon monoxide tester.It’s highly recommended to add a carbon monoxide tester in every bedroom or just outside the bedrooms.


Is a boiler the same as a hot water heater?

No, boilers and water heaters are different. They function differently. Boilers heat the home and provide hot water. Water heaters only provide hot water. They also require care and maintenance. There are also signs that a water heater is breaking.

Do You Need a Gas Boiler or Heating System Repair?

Get free, zero-commitment quotes from pro contractors near you.

What We Learned

An astute homeowner will be aware of changes with their boiler. Although explosions are rare, recognizing signs of trouble early can help prevent a boiler explosion.

Boilers are a pleasant and efficient home heating option. There are potential risks with all home heating options but these can be mitigated.

Upgraded Home Team
Upgraded Home Team

We are a team of passionate homeowners, home improvement pros, and DIY enthusiasts who enjoy sharing home improvement, housekeeping, decorating, and more with other homeowners! Whether you're looking for a step-by-step guide on fixing an appliance or the cost of installing a fence, we've here to help.

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