The 1 Unexpected Sign Your Boiler Needs Urgent Repair

Those noises are only one symptom.
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Now that it’s winter, your boiler is likely becoming the most important appliance in your home.

And if it’s broken or otherwise damaged, the effects on your gas bill can be huge (in fact, an inflated gas bill can be one of the first signs that your boiler is bust).

Many of us know to listen out for signs of failure with boilers ― loud gurgling can indicate trapped air, whooshing or vibrating can mean anything from a blocked flue to poor pressure, banging can be due to overheating or a faulty thermostat, and whistling can be a sign of limescale or rust.

But it turns out that there’s another sign of distress to look out for ― depending on the scent, it turns out that a foul smell could indicate a serious issue with your boiler.


Yep! That’s because gas companies put an odourous blend into gas to make its smell more noticeable. This has a rotten egg-like scent (ooh, lovely).

So, smelling the fetid scent could be a sign your boiler is leaking gas. In that case, you should take action immediately.

National Gas advises you:

  • Do not smoke or light matches
  • Do not turn electrical switches on or off
  • Open doors and windows
  • Turn off the meter at the control handle unless the meter is in the cellar
  • Call the National Gas Emergency number (0800 111 999) if you suspect gas. It’s better to be safe than sorry.

What if it’s not gas?

If you’ve made sure your gas levels are safe and still have a smell issue, there may be other causes of bad smells.

For instance, a burning metal, molten plastic, or burning oil smell could be due to frayed electrical wires ― in this case, you should immediately switch your boiler off and bring in an expert.

Sickly, rotting smells could come from mould buildup in your boiler. “Being a system that works with water and moisture, the risk of mould can be high if your boiler begins to leak a bit, which can spread mould to nearby flooring, furniture, and cellulose (wood) based materials,” appliance experts at John Nugent & Sons say.

Meanwhile, a straightforward burning smell that comes on when you switch your boiler on could be due to a simple dust buildup on your boiler or radiators. In this case, switch the boiler off and give everything a deep clean.

Again, though, don’t ignore gas smells ― call 0800 111 999 the second you suspect a leak.

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