Why does my boiler smell of gas?

31 March 2024

Experiencing a gas smell coming from your boiler is a distressing situation for any homeowner or tenant. This unusual odour shouldn’t be ignored, as it signifies a serious safety concern. In this article, we’ll explore why this might occur, what immediate actions you should take to ensure safety and how a bit of basic self-diagnosis can be helpful.

However, remember, when it comes to gas leaks, your most important action is always to ensure safety first, followed by calling in professional help.

Understanding why your boiler smells of gas

A basic bit of self-diagnosis might be helpful if you suddenly find gassy smells coming from the boiler area, but look to the immediate safety actions below first, because your actions in the next few minutes could save your life and your property. The most common causes of gas coming from your boiler are:

  • Leaking gas valve or pipes: The most likely reason is leakage in the gas valve which supplies gas to the burner, or pipelines inside or leading to the boiler.
  • Faulty burner: A damaged burner can lead to incomplete combustion, causing gas to escape.
  • Poor ventilation: If your boiler is in a small room or cupboard, inadequate ventilation can trap gas fumes inside, causing the smell. That doesn’t mean there isn’t an issue to fix, however. Even in an enclosed space there should be no smell of gas.
  • Cracked heat exchanger: This critical part, if cracked, may lead to gas leaks along with posing significant health risks due to carbon monoxide leakage.

Doing a visual check might give you clues about where the problem lies. Look for visible cracks on the body of the boiler or signs of wear and tear on connections and pipework. However, this is no substitute for a professional inspection. Remember, tampering with your boiler without appropriate knowledge or tools can make the problem worse and jeopardise safety.

Immediate safety actions

If you detect a gas smell coming from your boiler, it’s imperative to act quickly and safely to ensure the safety of everyone in the building. Gas leaks pose a serious risk of fire, explosion and carbon monoxide poisoning. Here’s a list of immediate actions you should take:

Avoid igniting gas

Don’t use any items that could trigger an ignition. This includes not just light switches, torches and mobile phones but also doorbells and appliances. Smoking, lighting candles or any other sources of flames or sparks are out of the question. 

Ventilate immediately

Ventilate the room by opening doors and windows as quickly as possible. This helps in reducing the concentration of gas in the air by letting gassy air out and fresh air in. It’s vital in preventing the accumulation of gas to dangerous levels.

Switch off boiler

If it’s safe, turn off your boiler to stop further gas flow. Do this only if you can access the off switch without any risk; never compromise your safety to perform this step. If your circuit breaker (fuse box) is far away from the boiler, consider switching off the property’s electrics to be extra safe. If the fuse box is close to the boiler, however, switching it might create a spark risk, so leave it to the experts.

Shut off the main gas supply

Locate your main gas valve, which is usually situated near the gas meter. Turn it to the off position. This step is crucial in halting the flow of gas into your property, thereby preventing further leakage.

Evacuate the premises

If the smell of gas persists or if you’re unsure whether it’s safe to stay indoors, evacuate the property. Prioritise getting everyone out of the building quickly and safely before investigating further or taking additional steps. Avoid lifts and consider alerting neighbours if you feel there’s a risk.

Call 0800 111 999

Once you are in a safe location, away from the affected building, call emergency services or the National Gas Emergency Service (0800 111 999) to report the situation. Be prepared to provide as much information as possible about the location and nature of the gas smell.

Do not return to the building

You’ve done all you can in the house for the moment. Wait for emergency services or professionals to declare it safe before re-entering your home. Returning too soon can endanger lives if the leak has not been fully resolved.

Schedule inspection and repair

After emergency services have addressed any immediate threat, contact a registered boiler repair specialist to inspect your boiler and heating system comprehensively. It’s crucial to identify and rectify the root cause of the smell to prevent future incidents.

Avoid covering up or ignoring the smell

Masking the smell with air fresheners or assuming it will dissipate on its own is extremely dangerous. Addressing a gas leak promptly is vital for safety.

Stay informed on safety procedures

Knowing how to turn off your gas supply and having a plan for quick evacuation can save lives in an emergency. It might be too late this time, but regularly review safety procedures with all the building’s occupants so they know what to do. 

Stick to your boiler’s service plan

There are many good reasons to make sure you book a service for your boiler every 12 months. For starters, you keep your boiler running smoothly and efficiently. You’ll also make sure your warranty isn’t invalidated. 

But one very important reason is that it keeps the boiler safe. Boiler engineers spend all their working days examining boilers, and they often spot early signs of wear or damage straight away. In addition, they have detectors and gauges that look for telltale signs of leaks and damage.

Remember: that annual service won’t just save you money – it could save your life and your property.

Taking immediate, decisive action upon smelling gas coming from your boiler can prevent death, injury and damage. Always prioritise safety by evacuating when in doubt, turning off the gas supply, ventilating the area and calling professionals from a secure location.