What to do in a Carbon Monoxide Leak From Your Boiler
A carbon monoxide (CO) leak from your boiler is a life-threatening emergency. CO is invisible and odourless. You won’t know it’s there until symptoms hit. The solution: know the warning signs, act fast and get a Gas Safe engineer to inspect your boiler. Here’s exactly what to do.
What Is Carbon Monoxide and Why Is It So Dangerous?
Carbon monoxide is produced when fuel doesn’t burn completely. Gas, oil and LPG boilers all rely on combustion. If something goes wrong, CO can build up fast.
It’s dangerous because your body absorbs it in place of oxygen. Red blood cells carry CO instead, starving organs of what they need.
The numbers are stark:
- Around 20 people die from accidental CO exposure in England and Wales each year, (UK Health Security Agency).
- 68% of carbon monoxide deaths in England occur in winter or autumn, (UK Health Security Agency).
- In 2020, only 46% of English homes had a CO alarm, (UK Health Security Agency).
You cannot smell it, see it or taste it. That’s what makes it so deadly.
What Are the Signs of a Carbon Monoxide Leak From a Boiler?
Your boiler may be leaking CO if you notice any of the following:
- The pilot light keeps going out: repeated failure to stay lit is a red flag
- Dark or sooty staining around the boiler: signs of incomplete combustion
- Excess condensation on windows near the boiler
- Yellow or orange flame instead of a crisp blue one
None of these guarantee a CO leak. But any one of them warrants immediate action. Don’t wait to see if it gets worse, repair it now.
What Are the Symptoms of Carbon Monoxide Poisoning?
CO poisoning symptoms often mimic flu, without the fever. If multiple people in the house feel unwell at the same time, that’s a major warning sign.
Common symptoms include:
- Headaches
- Dizziness or nausea
- Confusion or difficulty thinking clearly
- Shortness of breath
- Loss of consciousness
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Symptoms tend to ease when you leave the property and return when you go back inside. If that’s happening, get out and call 999.
What Should You Do If You Suspect a Carbon Monoxide Leak?
If you suspect a carbon monoxide leak, act immediately. Do not stop to investigate further.
- Turn off your boiler at the mains
- Open windows and doors to ventilate the property
- Leave the building: get everyone out, including pets
- Do not use any electrical switches on your way out
- Call the Gas Emergency Helpline: 0800 111 999 (available 24/7)
- Seek medical attention: even if symptoms seem mild, go to A&E or call 111
- Do not re-enter the property until cleared by a professional
Once the emergency is resolved, contact a Gas Safe Registered engineer to inspect your boiler before using it again.
Can All Boiler Types Leak Carbon Monoxide?
Can you get CO poisoning from a gas boiler? Yes, gas boilers are one of the most common sources of CO leaks. They rely on the combustion of gas. If the burner is faulty or the flue is blocked, CO can escape into your home.
Can you get CO poisoning from an oil boiler? Yes, oil produces CO when it doesn’t burn fully. Oil boilers carry the same risk as gas boilers and require the same level of regular maintenance.
Can you get CO poisoning from an electric boiler? No, electric boilers don’t burn fuel, so they cannot produce CO. They are not a CO risk.
Can you get CO poisoning from combi boilers? It depends on the fuel. A gas combi boiler can leak CO. An electric combi boiler cannot.
How Do You Prevent a Carbon Monoxide Leak From Your Boiler?
The best protection against a carbon monoxide leak is prevention. Two things matter most:
A Gas Safe engineer checks combustion, inspects the flue and spots faults before they become dangerous. Most CO incidents involve appliances that haven’t been recently serviced.
2. A working CO alarm
Install an audible CO alarm that meets British Standard EN 50291. Test it regularly. It’s the only reliable early warning you’ll get.
If you’ve had a scare, do not turn your boiler back on until a Gas Safe Registered engineer has inspected it. This is non-negotiable. At GK Plumbing, our engineers are Gas Safe Registered and experienced. Ready to act across Aylesbury, Milton Keynes, Oxford, High Wycombe, St Albans and the surrounding areas.
Get in Touch With GK Plumbing
Whether you need a boiler inspection or urgent advice, we’re here to help. Contact us today with any questions, or explore our full range of boiler and plumbing services.
