Skip to main content

Boiler maintenance

Winter can be a demanding time for your condensing boiler, and in recent years a record number of households have reported burst pipes and broken-down boilers. There's nothing worse than finding yourself without heating in the middle of winter, just when you need your boiler most. Sadly, that's when problems are most likely to occur. Thankfully, there are many boiler maintenance tips you can use to make sure you don't end up with a nasty bill when you’re forced to call someone out to fix a broken boiler. After all, even a cheap boiler could cost around £1,000, so it's better to be safe than sorry when it comes to boiler maintenance.
Share this guide
Person maintaining boiler

Why is boiler service and maintenance important?

Regular boiler checks ensure your heating system continues to run smoothly and efficiently. Regular cleaning and servicing can also detect problems before they become serious (and potentially more expensive) and prevent other issues from occurring.

How do you maintain a boiler?

You need to get your boiler serviced regularly by a Gas Safe registered engineer. You can set yourself a reminder to contact someone once a year or consider investing in boiler cover. Not only does cover for your boiler provide peace of mind from it failing at a crucial moment (say in the depths of winter), but most plans include a free annual boiler checkup too.

What to look out for

The most important requirement of good boiler cover isn't the price; it's the standard of service. Any work done on your boiler should be carried out through a Gas Safe Register engineer.

Only Gas Safe Registered Engineers are legally permitted to work on boilers in the UK, which provides you with the peace of mind that the work is being done safely and to a high standard.

Just ask to see your boiler repairman's Gas Safe Register card and look out for the yellow triangular symbol. 

What does boiler maintenance include?

A boiler service should include the following checks:

  • Visual inspection of the boiler and flame

  • Flue (both internal and external parts)

  • Operating pressure and input heat

  • Case seals

  • Safety devices

  • Removal of case to inspect boiler components, including heat exchanger, burner and main injector

  • Firing of boiler to spot any potential faults

If necessary, boiler parts will be cleaned, which may (or may not) include your pipes being flushed using a specialist cleaning material. You should also receive a service report showing all the tests and work that’s been done. 

What could go wrong with my condensing boiler?

Condensing boilers are the most common type of new boiler. They’re a godsend to households fighting higher gas and electricity costs, but can require more frequent boiler servicing.

The good news is that condensing boilers are 10-20% more efficient than regular boilers. The bad news, however, is that the system is more likely to freeze up in cold temperatures. This makes it important to have your gas boiler regularly serviced.

Things that can go wrong include:

  • A frozen condensate pipe – this can occur if the temperature outside drops below freezing; your condensing boiler will stop working or display an error.

  • Gas leak – if your boiler’s blue flame turns orange or yellow, this could indicate a problem. Call your boiler engineer immediately and check our guide to detecting and preventing gas leaks.

  • Boiler pressure – if it suddenly drops or rises, or the pressure remains too high for prolonged periods of time, you should get your boiler serviced.

Other symptoms to look out for:

  • No hot water or heat – the most obvious sign of a dodgy boiler is when it’s no longer heating water.

  • Clanking or ticking noises, particularly when your boiler starts up.

  • Higher gas consumption – keep an eye on your meter and bills. If consumption rises for no obvious reason, get your boiler checked over as soon as possible.

How to stop your condensing boiler from freezing

Gas boiler repairs can be costly, so remember that prevention is always better than cure. Start by taking steps to prevent your boiler’s pipes from freezing. According to the Heating and Hotwater Industry Council (HHIC), "setting the heating timer/room thermostat to continuous is one way to prevent the condensate pipe from freezing up." This is a great way to avoid shouldering an expensive boiler service cost.

The most energy-efficient way to do this is to leave your heating on low constantly. While it’s likely to cost slightly more to have your heating on all the time, you may save on the cost of an expensive repair and gain some peace of mind knowing your pipes won’t freeze.

This strategy may not be practical all the time, but it can pay off during particularly cold stretches of winter weather – be prepared to raise the thermostat to increase the boiler temperature and reduce the amount of condensate forming.

How to thaw a frozen pipe on a condensing boiler

If you’re unfortunate enough to end up with a frozen condensate pipe, your heating will grind to a halt, but thankfully it’s a problem easily remedied.

Most frozen condensate pipes are external, and this is where you’ll almost certainly find the blockage. Once you’ve identified where it is, try holding a hot water bottle, warm cloth or microwaveable heat pack around the frozen part. If this doesn’t work, try pouring hot (not boiling) water over the affected part of the pipe (be careful as the water may quickly freeze as it hits the ground).

Once done, you may need to reset your boiler if it doesn’t automatically do so. Be prepared to do this several times to thaw the pipe properly.

What happens if it keeps freezing?

While the above is a great short-term solution, it's of little use if you have to repeat it every day (or even multiple times a day). If frozen pipes become a recurrent problem, you may wish to invest more time and effort in making the pipe less susceptible to freezing. Consider some of the following steps:

  • Consider getting the pipe moved somewhere inside.

  • Look to replace the pipe with one with a wider diameter.

  • Try fitting foam pipe insulation around the pipe.

  • See if your boiler manufacturer provides a form of antifreeze (Worcester Bosch offers CondenseSure, which works up to -15° C) and have this retrofitted or added when installing a new boiler.

If none of the above help, the problem may lie elsewhere, in which case it's probably time to call in an engineer.

How to check and maintain your boiler

Boilers often break down in winter, which is the worst possible time to be living in a cold house with no hot water and no access to readily available boiler servicing.

What's more, the cost of calling out a boiler engineer is expensive and can involve lots of calling around to try and find someone who’s available to come out quickly, particularly during a period of bad weather when demand is likely to be greater.

That's why it's a good idea to sign up for boiler cover – that way you’re protected if something goes wrong, and with some plans, you even get an annual cheap boiler service included in the cost. Signing up to a gas boiler servicing contract could be a real life-saver if something goes wrong when the temperature outside drops, while also helping reduce boiler service costs.

Top tips for maintaining your boiler

The following tips can be performed to help keep your heating system running effectively:

  • Make sure your boiler is serviced at least once a year.

  • Check your radiators to see if they need bleeding at least once a year.

  • Perform other radiator checks: if they’re hot at the top and cold at the bottom, they’ll need a power flush (get this done during its next service or call out an engineer). 

  • If a radiator valve is open all the way but the radiator isn’t working, the valve may need replacing.

  • Check boiler flame is blue. If it’s not, you may have a gas leak.

  • Ensure the boiler is well-ventilated: avoid packing stuff around it, and make sure it’s fitted with at least 60 mm clearance if housed in a cupboard.

  • Check the boiler pressure: check the pressure gauge on the boiler readout. It should be between 1 and 2 bar. Check your boiler manual to see how to adjust this manually if required.

  • Check the external condensate pipe: if it’s dripping water then contact a local heating engineer to check the pressure release valve.

  • Make sure your flue is accessible: regulations require this to be visible and accessible so faults (loose joints, cracks) can be detected.

  • Never repair a boiler yourself.

FAQs