Warning signs that your boiler could be in trouble

UK Home Improvement

Warning Signs That Your Boiler Could Be In Trouble

It goes without saying that boilers in our house can be one of the most important elements of a working home. No one would want to live in a home without a working boiler. No working boiler means we are left with two big problems, no hot water and no heating.

Aside from the problems of not having a central heating system, neglecting your boiler for too long can cause major issues for your home. Broken boilers can leak poisonous gasses and even explode if prompted.

So, we’re going to go over some of the basics you should look out for when checking in on your boiler.

The Smell

A highly functioning boiler in its prime won’t omit any bad smells or odours at all, really. So, if you can smell anything out of the ordinary when investigating, such as spent flames, burning or something you simply don’t recognise, switch it off immediately.

It’s not worth leaving it on for the sake of a few more minutes of heating if you smell something out of the ordinary. There are a few different types of smells that you can look out for if you’ve not got a great sense of smell yourself.


If you notice any black or dark coloured stains either on your boiler or around, then It’s time to take caution.

It could be a sign of leaking around or on your ‘flue’. If you’re not sure what a flue is, it essentially refers to the pipework that moves the excess air and gasses from the inside of your boiler to outside. You may know it as the outlet duct outside your home, sometimes on the side of the house.

It’s an important component of a working central heating system and actually can be efficient in dispelling gasses back into liquid.

It’s fair to say that if you notice anything out of the ordinary, don’t try to fix and clean this yourself. These leaks could be a leading cause for carbon monoxide appearing and poisoning you without you even noticing.  

Professionals Find Faults

Boilers in your home are technical machines. You really shouldn’t be messing around them as they could end up erupting into flames and causing serious injury. If you feel as if anything in this list, even if it seems small, is relevant to your boiler then get an assessment immediately. Your boiler also needs a regular service, and if your boiler engineer notices something wrong, then you need to discuss it with them.

There are businesses out there that specialise in servicing boilers, installing new ones and giving you peace of mind. For example, GK Plumbing, who operate in and around the Oxford area, can be out within 24 hours if the boiler completely shuts down leaving you with no heating.

They also operate as an overall heat specialist in Oxford, meaning that not only do they work on boilers but they can also do general plumbing for your home, refit bathrooms and taps and provide gas certificates for landlords and tenants.

The benefit to having a local plumbing specialist is that you can feel safe and sort out issues before they become major problems. It’s a cost-effective method too as getting early repairs and check ups is better than major repairs down the line if you ignore what’s going on with your boiler.

Potential Condensation

Another sign of trouble within your boiler, something that you might not have even considered is a build up of condensation in the room where the boiler is installed. This would show you that the ventilation of your boiler is poor and the mist in your windows is actually exhaust gasses being released into your home instead of outside.

Water is a natural by-product of combustion but has no place staying inside your home, so if you’re seeing this ensure you take care and get it investigated.

Carbon Monoxide

We’ve touched a bit about the dangers of carbon monoxide so far, but it’s important you know what this actually is and the dangers it poses.

Carbon Monoxide is an odourless, colourless gas that is created when the combustion of fuel is incomplete. Which is why this gas is so common with broken boilers. The danger of this gas is, as it doesn’t smell and you can’t see it, is that you won’t know it is in the air until it starts affecting you.

Some of the symptoms to watch out for include:

  • Feeling weak
  • Being dizzy
  • Shortness of breath
  • Blurred vision
  • Confusion/feeling like you’re about to lose consciousness
  • Headaches

These are all very noticeable things to appear in a short amount of time, so you’ll certainly be aware that something is wrong, don’t ignore these warnings. The effects could be subtle but they’re certainly noticeable when you know what to look out for.

Make no mistake, carbon monoxide poisoning left unattended will kill you. When it gets into your bloodstream, it will slowly replace the oxygen in your red blood cells, leading to serious damage to your body and eventually death.

If you feel like you have carbon monoxide poisoning, get outside into fresh air and seek emergency medical help immediately.

Carbon monoxide poisoning can be particularly dangerous for certain risk groups of people, especially unborn babies, children and the elderly. If it doesn’t kill, it can cause irreversible brain damage. The damage can potentially be worse if you’re unconscious/sleeping.

If you’re still unsure of the practical side of it, it’s still worth installing a carbon monoxide detector in your home for your own safety.


If you’ve had your boiler for a while, you’ll know just how long it takes to warm up and start operating at capacity. Therefore, it stands to reason that if the times for heating up start adding up then something has gone wrong.

Modern boilers these days can reach max temperature rather quickly to start producing heat. So, if you find it takes hours then it could be due to a build up of sludge in your boiler. This will cause blockages in your radiators and leave dirty water within your system. Proving to be a problem further down the road.

Pilot Light

Your pilot light refers to the small gas flame, which is the primary ignition source for your boiler. It should stay on when you have your boiler on.

If it keeps going out it could mean the thermocouple needs replacing. This is a small device that goes into the flame. Without this device working properly, you will have inconsistent heating.

Costs And Bills

Another good indicator that something is amiss with your central heating system, is if your bills are higher than normal.

This is common with older boilers, the older they are the more inefficient they are at their job. Meaning they start costing more to run at the same level.

You can get boilers checked for their efficiency by experts and they’ll analyse their gas record and ratings. There are lots of opinions on how much money you can save on switching from old boilers to new and it’s certainly worth researching your boiler.

Be Safe

It’s important that we understand the significance and complication that goes into our boilers and heating systems. There are plenty of experts out there who are well trained in how to best fix and assess.

Don’t mess around with what you don’t know. Turn your boiler off if any of the issues raised in this article are applicable to you.


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