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Main Boiler Service & Maintenance

Rob Wells
By: Rob Wells
Updated: 9th December 2021

A Main boiler could provide your home with heating and hot water for 10-15 years after installation but it will need to be well looked after.

Taking care of your boiler can be made simple with an annual boiler service. An annual service by a Gas Safe engineer will give you the peace of mind that your boiler is running safely and as efficiently as possible to keep those heating bills to a minimum.

Is your boiler due a service?



What is a boiler service?

A boiler service should be carried out annually by a fully-qualified heating engineer. The service will involve a series of checks and tests to ensure that the boiler is running safely and efficiently.

When it comes to gas boilers, only a Gas Safe registered engineer can carry out a boiler service, if you have an oil boiler then the engineer must be OFTEC registered.

For gas boilers by Main, you need to find a Gas Safe registered engineer which means they are listed on the UK's official list of engineers legally allowed to work on gas appliances. You can check if an engineer is registered by visiting the Gas Safe Register website and you should always ask to see their Gas Safe ID card when they arrive to service your boiler.

From start to finish, a boiler service should last at least 30 minutes but this time will differ depending on the type of boiler and whether the engineer comes across any issues.

Boiler service checklist

You shouldn't allow the engineer to begin work on your boiler until you've checked that they're fully qualified. You can do this by asking to see their Gas Safe card. After this, the engineer will carry out some standard efficiency, operational and safety checks:

  1. To begin, the engineer will inspect the boiler to check for signs of corrosion or leaking and also make sure that the flame burns blue.
  2. They will then remove the boiler casing to have a look at the inside of the boiler; cleaning many of the parts such as the heat exchanger, burner, main injector, safety devices and spark probe.
  3. It will then be a case of checking that the flue terminals are fitted safely and that nothing is blocking them. They will also make sure that seals, water and gas pipework are all intact.
  4. They will check the gas pressure and flow settings to ensure they're at the correct level.
  5. The final part of a boiler service involves the engineer starting the boiler up so they can check for any faults in operation as well as issues with temperature controls or potential repairs.

After the service, the engineer will provide you with a service report detailing everything they've done during the boiler service. Don't hesitate to ask the engineer any questions you have about the report.

Is your boiler due a service?



Why it’s important to service your Main boiler


The safety of your home is one of the most important reasons for having your boiler serviced each year. During a service, the engineer will be able to spot any current or potential future faults that could cause harm such as a carbon monoxide leak.

A carbon monoxide leak is one of the biggest concerns when it comes to boilers and is hard to detect because it's colourless and odourless. A leak could quickly lead to brain damage or even death if it goes unnoticed. If you spot that the flame in your boiler is orange, rather than blue, there could be a leak, but don't wait until your annual service to find out. Contact a Gas Safe engineer right away.

Keep heating bills down

Everyone is looking to keep their heating bills as low as possible and an annual service is a great way to see how you could be saving. Over the years, a boiler will gradually lose its efficiency, increasing your energy bills. Having your boiler serviced each year will bring to light any components that have dropped in condition to keep the unit running efficiently for longer.

Prevent breakdowns

Even the smallest issue with the boiler could lead to a breakdown if left which is why finding them early is so important and having your boiler serviced will bring to light any potential faults so that you avoid a large bill for repairs.


The warranty is an important part of any boiler installation as it gives you the peace of mind that you're covered by the manufacturer should something go wrong. Main boilers tend to come with a warranty period of 5-7 years but to keep this valid, the boiler must be serviced by a Gas Safe engineer annually, otherwise you'll lose the warranty.

Main boiler service costs

The cost of a one-off boiler service tends to site somewhere between £60 – £120 but this will depend on the engineer carrying out the work, where you live and the model of boiler.

As engineers tend to be at their busiest during the winter, you could save a bit of money by getting your boiler serviced during the summer. Summer is also a great time for a boiler service because it means that any faults can be spotted and resolved before the temperature drops and you need the boiler the most.

NEVER try to carry out a boiler service yourself. Always find a Gas Safe registered boiler engineer.

Is your boiler due a service?



Boiler service plans

You can keep your boiler covered by taking out a boiler service plan. Boiler service plans cover your boiler for a 12 month period and include an annual service so you don't have to pay the full fee there and then, instead, you would be paying a monthly fee which also covers you for any repairs.

When you consider that a boiler service plan can cost over £100 every year, it can make more financial sense to pay the one-off fee for an annual service as and when required. However, boiler cover and service plans can provide a peace of mind that you won't have to put the money together to cover the repair costs if the unit breaks down. Well worth considering if your boiler was installed more than 8 years ago, or no longer covered by a manufacturer warranty.

Boiler maintenance

There are a few checks you can make yourself during the year to keep your boiler running as efficiently as possible, as well as arranging an annual service.

Insulate the pipes

During the winter, pipes can freeze and cause blockages which can then lead to a rise in boiler pressure, leaking or even cause the boiler to completely breakdown. To combat this, you can insulate the pipes using lagging such as mineral or glass wool, polyethylene or foam.

Check the pressure

To make sure that the boiler pressure is where it should be, regularly check the pressure gauge. The ideal reading is somewhere between 1 and 1.5 bar; any lower and the boiler might not be able to ignite, too high and some serious damage could be caused. If you find that your boiler's pressure isn't between 1-1.5 then you can sort this yourself, without the need for an engineer, by consulting the instruction manual that came with your boiler.

Insulate your home

Your boiler can be running to its maximum efficiency but you won't feel the benefit unless you have a well insulated home.

Annual service

While there are lots of things you can do to help your boiler and central heating system run efficiently, an annual service is the best thing you can do for your boiler. It can be easy to put off arranging a boiler service due to the cost but it could save you from having to pay a large repair bill further down the line.

The easiest way to find a Gas Safe registered engineer to service your Main boiler is using Boiler Guide. You can get a free quote from a local heating engineer by letting us know that your boiler needs a service. Once you’ve done that, the engineer will soon be in touch to arrange a quote.

Go back to the Main boiler page.

Is your boiler due a service?



Rob Wells

About the author

Rob Wells

Rob is another of our resident home heating experts. He manages our external partnerships, making sure you get the most up to date information.

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