How to keep your boiler working in cold weather - and what to do if it's broken

As many of us have learned the hard way over the years, extreme cold weather can stop your boiler from working. Here's how to avoid a home disaster as winter sets in.

As well as preventing energency call-outs, it's important to make sure you look after your boiler over winter to keep it working efficiently.

A big drop in temperature can cause problems such as loss of boiler pressure, frozen condensate pipes, frozen pipes and radiators not working. 

Read on to find out what to do if your boiler does stop working and some of the things you can do yourself to keep everything running smoothly. 

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What to do if your boiler breaks down in winter

If your boiler is acting up for one of these common reasons, here's what you can do about it:

• Loss of boiler pressure - You can increase your boiler's pressure yourself if you know what sort of filling system you have, eg an internal loop or external loop. Your instruction manual should tell you what type you have and how to top up the boiler. If you've lost the manual, you may well be able to find instructions online or the manufacturer should be able to talk you through it over the phone. We also have a video on how to repressurise your boiler. 
• Frozen condensate pipes - If your boiler is making a gurgling sound and shuts down, it may be that your condensate pipes have frozen. If your boiler has a digital display, check whether an error message is appearing. You'll then need to locate the frozen pipe, thaw it (using warm, not boiling water) and reset your radiator. Our guide to thawing a frozen boiler condensate pipe goes into more detail. You can also disconnect the condensate pipe from the boiler and catch the water in a bucket. If you're at all unsure which pipe to disconnect, consult an engineer instead. You should have it reconnected as soon as possible. 
• Problem with the boiler or thermostat settings - If your boiler won't fire up, or comes on unpredictably, or you can see an error message on your thermostat, your timer settings might have somehow changed. Check your manual and adjust them if you need to. You might need to reset it, which is a quick job. If you keep needing to reset it, call an engineer to take a look at the underlying issue. If your boiler isn't responding to your thermostat, the controls could be broken. Also try changing your thermostat's batteries if it's wireless, obvious as it sounds. 

If the above doesn't work, you can't figure our what's wrong with your boiler or anything more worrying is happening (it's giving off a strange smell, for example), it's absolutely time to call in an engineer. 

See our guide to common boiler problems and repair costs to find out how much you should expect to pay if your boiler develops a fault.

If you're more vulnerable, it's especially important to call an engineer promptly if you've got no heating, as living in an underheated home can significantly increase your risk of falling ill. 

How to prevent your boiler breaking down in cold weather - DIY tips

Sometimes a boiler breakdown is unavoidable, however diligent you've been in looking out for warning signs. But, there are a few things you can do yourself. 

• Don't forgo your annual boiler service - This will flag any potential issues before they become a problem and your engineer will also be able to make sure it's running as efficiently as possible and keep your warranty valid (if it's still under warranty).
• Don't ignore anything unusual - After getting a boiler service, this is the most important thing you can do to avoid your boiler breaking down on you just when you need it most. If your boiler is losing pressure quickly, there's water trickling down the wall that the boiler is fixed to, or you can see mould or stains around the boiler, this could indicate a water leak. Black stains above or near the boiler, large amounts of condensation on your windows, or a pilot light burning orange or yellow rather than blue (if your boiler has a pilot light) could indicate a gas leak. If you suspect a gas leak, open all your windows or doors, call Gas Emergency Services for free on 0800 111 999 and don't operate any electricity or light any flames. You should already have a carbon monoxide alarm - test it regularly to ensure it's still working, as carbon monoxide is odourless. If you don't have one, you should buy one asap.
• Check your boiler pressure - Take a look at your boiler's pressure gauge. It should be at the 1.5 bar. If it's below 1, it won't be able to work properly and you'll start to see error messages or experience problems (see more, below). If it's too high, bleeding your radiators can relieve pressure. 
• Insulate your pipes - It's a good idea to insulate your pipes with lagging (long foam tubes) to protect them from freezing over. If you have a condensing boiler, the wastewater vapour flows out of your home slowly, which puts them at risk of freezing. You can buy lagging cheaply from many hardware stores. In particular, insulate the pipes outside your home, if you can. 

Another winter job you may need to do is balancing and bleeding your radiators. These are two entirely different things, but the aim in both cases is to make sure that your home is evenly heated. 

Cold patches are often caused by an accumulation of sludge or air inside radiators. If you have warm and cold areas across your home, you may well need to balance your radiators, while they likely need bleeding if individual ones are warmer in some places than others. 

Radiators need bleeding (pictured below) every couple of years to remove trapped air bubbles. You'll need to switch off your central heating and let your radiators cool down before doing this. Our guide explains how to balance and bleed your radiators. 

Get the most from a boiler service

If you haven't already done it this year, you should get your boiler serviced. You should aim to get your boiler serviced in summer, and in good shape ready for winter, because gas engineers are much less busy during this time. But if you didn't get around to it, book one in now as a preventative measure. 

Not only will it save you money by preventing an expensive repair job, not doing so could invalidate your warranty and have serious safety ramifications. 

Could you be eligible for the government's free boiler scheme? Find out if you might be able to get a free boiler or boiler grant

Boiler service near me

Whether you're booking your regular boiler service or looking for a boiler repair, use our Trusted Trader tool below to find a boiler engineer that you can be sure will do a good job. 

Once you've booked one in, find out more about getting a boiler service to make sure you're asking all the right questions when your engineer arrives. 

If, in a worst case scenario, you need to buy a whole new boiler, make sure you know which are the best and worst boiler brands.