Gas Safety Week 2020: Signs your boiler could be faulty: red flags to look for

How to tell if your boiler could be dangerous

On the whole, gas boilers are very safe and while any boiler can go wrong and result in loss of heating or hot water, there are fail-safes built in that will usually prevent the boiler becoming dangerous. That said, although rare, it is always a possibility that it can happen and the older it is the more risk it poses. Everyone should therefore know the red flags that tell you that your boiler could have become unsafe. – it could just save your life.

1. The smell of gas

It sounds fairly obvious but the smell of gas is a clear indication that the boiler (or another gas appliance) is likely to be leaking. The smell is likely to be stronger around the area of the boiler or could even be detected outside where the flue comes out.

If you do smell gas you should call the National Gas Emergency Service, operated by the National Grid immediately on 0800 111999 who will be able to send an emergency engineer out. In the meantime, ventilate the house by opening the windows and wait outside the property if you can. The operator will be able to advise you on what you need to do.

Please note that this is not something that a general gas engineer can help you with, it should always be the National Gas Emergency Service in the first instance.

2. Feeling nauseous, dizzy or have constant headaches

These symptoms could indicate that you have carbon monoxide (CO) poisoning, which is caused by gas not burning completely. CO is highly toxic and can kill you very quickly. It is both odourless and colourless rather than waiting until you have symptoms of CO poisoning it is a much better idea to get a CO monitor that would alert you in the event of even a small leak.

If your alarm does go off, or you suspect you have symptoms of CO poisoning, turn off the boiler at the power, leave the property and call the National Gas Emergency Service. Carbon monoxide kills around 40 people a year and hospitalises around 200.

3. The pilot light burning yellow or constantly going out

Gas burns blue when it has the right amount of oxygen. If it doesn’t have enough oxygen it won’t burn completely and that’s when it can create carbon dioxide. A yellow, flickering flame or a flame that keeps going out can therefore be another sign of CO.

This can happen because not enough air is getting into the boiler to allow the gas to burn properly. The space that the boiler is in should always be well ventilated and the boiler should have plenty of clear space around it (don’t ever pile things on top of the boiler or stack furniture around it).

4. Signs of soot or scorch marks

Black stains near the boiler, often on the ceiling above, could indicate that there is a leak coming from the flue. This means that fumes that should be released outside, are seeping out inside. This could include CO.

5. Heavy condensation

Heavy condensation or misting up of windows in the area of the boiler could be a sign that it isn’t being vented properly. This is because water is one of the by-products of combustion. If exhaust gases aren’t being vented away properly, they could be being released into the home.

The best way to prevent your boiler becoming dangerous is to always use a Gas Safe engineer to install it and have it serviced every year. Keep a CO monitor near all gas appliances and keep the batteries up to date.

See all the blogs for Gas Safety Week so far here.