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Boiler maintenance guide

New boilers are pricey, so you want to make sure that yours goes the distance. Here’s how to look after your boiler so it keeps on working every winter.  

New boilers are pricey, so you want to make sure that yours goes the distance. Here’s how to look after your boiler so it keeps on working every winter.  

Written by
Anna McEntee
Home, pet and travel insurance expert
26 APRIL 2021
4 min read
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How do I look after my boiler? 

You’ll want to make sure your boiler stays in good working order. Parts can wear out over time, sludge can build up inside and adjustments may have to be made. When it comes to boiler maintenance, some things you can do yourself, but for others you’ll need a qualified engineer.  
If you’re a landlord and you’ve installed gas boilers in your properties, you’ll need to make sure they have an annual gas safety check too. 

So how do you maintain your boiler? 

  • Get your boiler serviced every year 

Yearly maintenance sounds expensive, but if your boiler goes wrong it could cost you even more to repair or replace it. Even if your boiler seems to be working fine, it’s not always possible to detect problems before they become serious. Plus, a regularly serviced boiler is an efficient boiler – which should mean you save on your energy bills.  
Try to get your boiler serviced in the autumn, before the weather turns cold. You’ll not only avoid getting caught out if there’s a fault, but it should be easier to get a convenient appointment as engineers won’t be dealing with winter emergencies.

You can expect to pay somewhere in the region of £80 to £130 for a service, depending on the age of your boiler and how long it’s been since the last service. See how to get a cheap boiler service.

  • Check the boiler flame 

The flame inside your boiler should be clear blue. If you’re able to look at it and it’s burning yellow or orange, that’s a sign you have a problem. It could mean you have a carbon monoxide leak, so turn the boiler off, open doors and windows, and get it checked straight away. Call the National Gas Service on 0800 111 999

  • Look for warning signs 

If your boiler’s leaking, making weird noises or you’re finding sooty marks on the wall – it’s time to call out a heating engineer.  

  • Get a carbon monoxide alarm and replace the batteries when necessary  

It’s possible for a boiler to leak deadly carbon monoxide (CO). In the UK it leads to around 50 deaths a year. You can’t see, smell or taste carbon monoxide, so it’s important to have a working alarm.  

It’s easy to get an alarm from DIY shops, large supermarkets and department stores, or online retailers and from some energy suppliers too.  Make sure the model you choose meets current European safety standards. Check the packaging or the product to see it complies with BSEN 50291 or EN50291 and has the 'CE' mark. 

Your alarm should be placed up high, between 1-3 metres from the gas, coal or oil fuel appliance you're monitoring for CO leaks. Alarms can be left free standing on a shelf or fixed to a wall or ceiling.  

  • If on a ceiling, the alarm should be mounted at least 30cm from any wall.  
  • If on a wall, the alarm should be mounted at least 15cm from the ceiling. 

What to do if your carbon monoxide detector goes off  

  • Open doors and windows to get fresh air in.
  • Turn off the appliance that has set it off.
  • Ideally, leave the property with the doors and windows open. 
  • Call the National Gas Service on 0800 111 999.  
  • Don’t go inside again until the alarm has stopped.
  • If anyone is showing any symptoms, get medical help immediately. 
  • Don’t use the appliance again until it’s been checked.  
  • Check your boiler pressure 

Boiler not working properly? Have a look at the pressure gauge on the front. If the needle’s in the red zone, consult your model’s instruction manual.

  • Listen to your boiler and your heating system

If the sound your heating system makes when it comes on is a bit like a kettle, you could have a build-up of sludge or limescale on your boiler’s heat exchanger. Boiler engineers call this kettling. This kind of build-up can restrict the flow of water in the heat exchanger, resulting in overheating, steaming and boiling. 

  • Turn your heating on occasionally during the summer  

Dust and corrosion can build up if your boiler hasn’t been used for a while. And even if you have a combi boiler for hot water, the parts of the system that heat up your home will be inactive when the heating’s off. It’s worth turning on your heating – just for 15 minutes or so – in the summer and autumn, to keep the boiler ticking over. It will help flag up issues early for you too.  

Not only will turning on your heating from time to time help your boiler, but if you have temperature valves on your radiators it means they’ll be less likely to get stuck, so won’t be a problem when winter comes.  At the same time, you can check whether you need to bleed your central heating system, so it will be working efficiently and cost-effectively come winter.   

  • Insulate your pipes 

Modern condensing boilers can be prone to a particular problem in freezing weather. This type of boiler is more energy efficient than traditional boilers because, instead of expelling hot waste gases from a flue, some of this energy is used to heat water. 

But this process condenses moisture in the gases. The subsequent waste liquid is carried down into the drains via a narrow plastic pipe – known as the condensate pipe - running down an external wall. It’s this pipe that can be prone to freezing in very cold temperatures. The waste then can’t escape, causing the entire system to back up and stall. To prevent the pipe freezing, it can be lagged, replaced with a bigger diameter equivalent less likely to freeze, or even routed differently so it’s less exposed and more sheltered.  

If you do find that the pipe is frozen, gently pouring warm (not hot or boiling) water over the pipe can melt the obstruction, standing as well clear as you can. If the water is too hot you could crack the pipe. But this is just a short-term solution and you’ll have to take steps to prevent it re-occurring. 

What to do if your boiler needs repairing

Firstly, don’t try to fix it yourself. Instead, contact a heating engineer. All UK heating engineers must be Gas Safe registered – you can find a local one by visiting Gas Safe Register

Boiler repairs can be expensive, typically £100-£400, but could cost more than that, depending on what’s wrong. See more about the costs of getting a boiler fixed.

Do I need boiler cover? 

Boiler cover will protect you from the costs of fixing your boiler if it breaks down. Whether you need it or not depends on the age and condition of your boiler, and whether you can afford to replace it, if needed.

What will boiler insurance cover me for?  

There’s essentially two different types of boiler cover: 

  • Breakdown/repair cover for when problems arise, so you can get them resolved as quickly as possible.
  • Maintenance cover – includes an annual service to keep your boiler running efficiently. 

Some policies will cover both situations. You can also opt for a policy that covers not just your boiler but your entire central heating system and its controls. Top-of-the range full home maintenance plans can also include plumbing, wiring, drains and waste pipes, and even pest infestations. 

Cover can vary, so check the policy to see if it covers: 

  • calling out an engineer 
  • annual boiler services 
  • parts and labour 
  • a discounted new boiler if your old one is beyond repair.  

How do I get boiler cover?  

There are three ways to cover you boiler: 

  • Add home emergency cover to your home insurance policy, checking first that boiler cover is included.   
  • Buy boiler cover from a specialist provider.  Compare the Market works with Hometree, one of the UK’s top-rated home care providers. 
  • Get a warranty or repair plan from the manufacturer.  

What to watch out for 

If you’re taking out a home emergency or boiler care plan, always read the policy carefully.  

  • Make sure your particular boiler is included in the policy. Some models won’t be, especially if they’re old or run on oil.
  • Check the conditions. For instance, you may need to keep your boiler regularly serviced to be eligible to make a claim. 

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