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First Choice Heating & Cooling Blog

Can My Boiler Overheat? Or Even Explode?

Boiler with pressure gauge and bright light in the background.

Boilers can overheat, and they can cause explosions in rare circumstances if the conditions are right. Let’s get this out of the way right from the start: if your boiler exhibits signs of overheating or runs the risk of exploding, this is an emergency and should be treated as such. That’s when you call for boiler repair as soon as possible.

Let’s talk about why it can overheat, what causes it, and the two different types of ways your boiler can explode so you know what the risks are.

Yes, Your Boiler Can Overheat

Your boiler is built with safety features in mind, but as we know, any part can fail and stop doing its job. Boilers can overheat for a multitude of reasons, and in extreme cases, they can explode. Here are the different ways it can overheat.

Removed Pressure Release Valves

Pressure release valves do exactly what you would expect them to: release pressure. Because they’re known to leak, some technicians and engineers remove them or seal them entirely to prevent leaks. This results in pressure buildup which can lead to an explosion.

Failing Thermistor

Picture the thermistor as an indicator. It decides whether or not you need more fuel (when your boiler needs to heat more water) or less. If it goes haywire, it can start to send the wrong signals and cause an abundance of fuel being sent to the boiler. Your boiler heats unnecessarily, then pressure builds and can result in an explosion.

Limescale Buildup

Your heat exchanger inside your boiler is subjected to minerals in your water supply. Over time, limescale can build up on the heat exchanger. This can sometimes create a whistling noise when your boiler turns on. The buildup of limescale results in hot spots throughout your boiler, where some areas are hotter than others. Because your heat exchanger has an obstacle, it may try to heat your water if it falsely detects that the water temperature isn’t high enough, resulting in pressure buildup.

Understanding Two Boiler Explosion Types

While this is only in extreme circumstances, your boiler can explode. There are two different types of explosions with varying consequences.

Explosion From Fuel-Related Problem

Combustible gasses can build when the ignition is out. Identifying the problem and reigniting the heat source for your boiler can result in a combustible gas explosion which may result in a fire hazard. There will be a loud bang and potential property damage.

Explosion From Pressure-Related Problem

When pressure builds inside of the boiler and there’s no way to release it, the system can burst. Pressure-related explosions are severe, although they typically don’t include a fire hazard. The exterior of your boiler will split, there will be a loud bang, and potential property damage.

Call for Professional Service as Soon as Possible

Boilers can overheat and potentially explode under the right circumstances. It’s important to identify the signs before a complete system breakdown (and before anyone gets hurt). This isn’t a DIY solution: you need to call a trained technician who knows what they’re dealing with, and how to be safe during the entire process. Don’t put your safety at risk.

Contact us today to inspect your boiler and identify any safety hazards as soon as possible.

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