How safe is my boiler?

A faulty boiler can have several knock-on effects. It can cost more to run, leave you without heat in the winter and, at worst, is dangerous. So how do you know which boiler issues are minor and which require more urgent action? We’ve looked at the most common boiler problems and given each a priority rating. 'Low' signifies it’s a minor issue, 'High' means you’ll need a Gas Safe engineer as soon as possible.

1. My heating and/or hot water isn’t working

A pressure or thermostat issue may be behind your heating or hot water not working. These can be simple to fix – see points 2 and 8 below. Alternatively, a broken part, such as a diaphragm or valve could be responsible, or it could be an airlock in the system. If you’ve addressed any pressure or thermostat problems and you’re still not getting heat or hot water, a Gas Safe registered engineer will be able to help diagnose other causes and fix them. Not dangerous but not ideal.

Is your boiler safe

2. My boiler has lost pressure

Boiler safety and whether you need a boiler service

Your boiler pressure should sit at 1.5 bar (this applies to boilers on a ‘sealed system’). If you’re having trouble getting heat from your system, low pressure could be the culprit. It’s easy to diagnose through a quick check of your boiler gauge and is usually easy to fix in a few simple steps. Lost pressure is a nuisance, but it’s not life-threatening. If you can’t put it right yourself, give a Gas Safe engineer a call.

3. My boiler is leaking water

You should never see water coming from your boiler. If you do, it might be a sign that an internal part has failed. While it’s not necessarily dangerous, you should switch off your boiler to prevent your electrics short-circuiting and to stop water damaging your home or belongings. Don’t try to fix a boiler leak yourself. Always let a Gas Safe engineer take a look.

How to hire a gas safe engineer

4. My boiler is making a lot of noise

Take out boiler insurance to cover the cost of boiler servicing

Gurgling, banging or whistling sounds should probably be looked at. They’re likely to be caused by air or a build-up of material inside your central heating. It’s not a dangerous situation but if left unattended, a build-up could lead to a boiler breakdown and expensive repairs.

5. My pilot light flame has changed colour

A pilot light turning orange or yellow could indicate poor combustion, which is very serious. Turn off your boiler immediately and have a Gas Safe engineer take a look at it.

You might also notice:

  • A smell of gas when your boiler is running
  • Scorching or brown/black marks on the boiler
  • A musty smell or signs of soot
  • More condensation than normal on your windows

If you suspect carbon monoxide or a gas leak you should immediately switch off your gas supply at the meter, open your doors and windows to let air into your home, and leave the house. Contact the National Gas Emergency line on 0800 111 999. Stay outside and don’t use electrical switches or naked flames until the experts have given it the OK.

Annual boiler safety checks

6. My pilot light keeps going out

Dangers of a gas leak

If this happens frequently — and especially if it’s combined with any of the signs above — your boiler should be checked over by a professional without delay.

7. My condensate pipe is frozen

Frozen pipes are a common cause of boiler shutdown, but the issue should resolve itself once the pipes thaw. Frozen pipes don’t pose much risk — unless anyone in your home is vulnerable to the cold. You can try unfreezing them yourself by pouring hot (but not boiling) water on the pipe end. A hot water bottle or other form of heat wrap might also work. After a while, switch the boiler off and on again and if it’s still not working, contact a Gas Safe engineer.

Checking for carbon monoxide leaks

8. My thermostat isn’t working

Boiler safety advice

A faulty thermostat isn’t dangerous, but it is annoying. So make a few simple checks – have the timings been accidentally changed or the temperature settings adjusted? Try increasing the temperature on the thermostat controls to see if it triggers the boiler into action. If it doesn’t and the thermostat seems to have become less accurate, or started doing its own thing, it might be time to replace it.

9. My boiler keeps turning itself off

Low pressure, a thermostat issue, or maybe lack of water in the system could cause your boiler to switch itself off. If you can’t identify the source of the problem, a Gas Safe engineer will. As with all boiler faults, it’s better to nip it in the bud. 

Boiler safety tips

To find a local Gas Safe engineer or check that a recommended tradesman is registered, look at the Gas Safe Register. Alternatively, use one of our expert engineers – they’re all Gas Safe registered, to come and look at your boiler and central heating system. They’ll talk you through the best options for your home and give you a fixed price quote.

If you’re signed up to our HomeCare plan, they will give your boiler a thorough check-up so you can feel reassured that it’s working as it should.