Category - Boilers
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Will Scholfield, Engineer

31 Jan : Updated 18 Apr ● 7 min read

How long does a boiler service take?

A boiler service usually takes around 20-40 minutes, depending on a number of factors, but can take a long as 1.5 hours for older boilers that need more work doing. The service must be always completed by a Gas Safe registered engineer. 

Many things need to be inspected and analysed during the service, and various parts must be properly cleaned. The length of the boiler service can vary depending on the model and make of the boiler, its age, and whether it's combi or conventional.

Older boilers may need a more in depth service and maybe even some parts or seals replacing, so the service may take longer. 

In this guide, we’ll help you to understand how long you need to allow when having your boiler serviced to help you to book it at a time that’s convenient.

What does a boiler service include?

Various things need to be checked and inspected during an annual boiler service, and what’s typically included is as follows:

Visual inspection

Your gas engineer will first need to inspect the boiler and ensure it meets current requirements and standards, this is an important first step in the service as it means that any obvious signs of incorrect installation or damage to the boiler is picked up before commencing any works. They will look for things like any leaks and corrosion, any regulations not followed on installation and any other physical and obvious defects inside and outside of the boiler.

Boiler casing removal

The engineer will then inspect each of the boiler’s main components to make sure that each part is working correctly. This way, the engineer can see if there are any defects. They will then clean the inside of the boiler and all of its components. These checks will include the burner, heat exchanger, pilot assembly if your boiler has one, and the combustion chamber for signs of corrosion or leaks.

Flue check

The boiler flue is the pipe that runs from the top of your boiler and terminates outside, within the required parameters set by the manufacturer who makes the boiler. The flue pipe requires a visual check to ensure its installed correctly and to regulations but it also requires a machine called a flue gas analyser connecting to it. The analyser just checks the gases within the flue to check the boiler is operating as it should, the qualified engineer must ensure the readings are within the required parameters set by the people who make the boiler. 

Learn more on what is a boiler flue

Checking boiler performance

The engineer will perform a gas performance check to ensure that your boiler functions at the correct pressure in accordance to the manufacturer's specification, this is essential as it ensures the boiler is getting enough gas to function correctly and safely.

Working faults check

The engineer will then run the boiler to ensure that everything is working correctly and efficiently. When looking for faults, the engineer will check the heating system, controls, the pilot assembly if it has one, burner, seals, safety devices, ventilation, and the boiler's location.

Once they have done all the required checks, the engineer will make a service report of their findings. You can then keep the record as it will be helpful in your next annual service and will help if any problems arise, as well as to ensure your boiler’s warranty remains valid.

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Does an oil boiler take longer to service?

Yes, servicing an oil boiler usually takes longer than a gas boiler. 

An oil boiler service generally takes about 1-2 hours, and it typically costs more than other boiler services do. This is mainly because the oil tank that stores the fuel needs to be visually checked, as does the boiler.

When should I get a boiler service?

You should get a boiler service 12 months after it has been installed; this is so that it can meet the terms of the warranty. After this, you should continue to get your boiler serviced once a year. 

If you notice anything unusual in your boiler, or you’re having problems with it, you should immediately call a gas safe registered engineer. You should contact an engineer if there are smoke marks or stains on the boiler, the flame is yellow, there is regular overheating, the boiler pressure keeps dropping, or if the pilot light goes out.

And a top tip… 

It is also recommended that you have your boiler serviced during the summer months, as you won't be using it as much at this time of year. This way, you can be sure that your boiler is ready and working properly during those cold winter months. 

Why it’s important to have your boiler serviced every year

Servicing your boiler is essential maintenance and should be undertaken every year. 

It is the responsible thing to do and will benefit you, your family, and your home. Here are the main reasons why servicing your boiler is so important:


Getting your boiler serviced regularly ensures that you and the people in your home are all safe. A boiler burns fuel, and you run the risk of it leaking carbon monoxide. Carbon monoxide is hard to detect as it is odourless, colourless, tasteless, and incredibly poisonous. This is a serious problem as you probably won't be aware that you are being exposed to it.

So by getting your boiler serviced, you can ensure that you are not putting anyone in danger, and you can have peace in knowing that everything is working and running efficiently and correctly.

Learn how often a boiler should be serviced

Preventing boiler breakdowns

If you regularly service your boiler, you can catch problems in the early stages and fix them before it causes any issues. Even the smallest of problems can lead to significant issues, and could potentially cost you a lot and may be a danger to your safety.

Maintaining a high level of efficiency

The older your boiler gets, the less efficient it becomes. Regular servicing will ensure that your boiler is running efficiently and will ensure the boiler lasts it’s estimated lifespan. Most boilers last about 10-15 years, but they could last you much longer with regular servicing and proper maintenance.

How much does a boiler service cost?

The boiler service cost depends on the type of boiler you have, the age of your boiler and whether any parts are needed. The older a boiler gets the more in depth servicing can become.  In order to clean internal parts, sometimes this requires servicing kits including new seals and gaskets that manufacturers provide and charge for, this is later in the life of your boiler and the gas engineer should be able to do certain tests and advise when this is needed. 

A combi boiler or other gas boiler service can cost between £100 and £200 via an annual servicing contract but a lot of contracts can include other cover. A one-off service can cost you between about £800 and £150, with £90 being the average across the UK. 

If the boiler is giving you multiple problems, even after it's been serviced, it may be time to get a new boiler quote. This will likely save you more costs in the long run.

If you want to learn more, check out our guides on what does a boiler service include. and when does a new boiler need its first service?

Frequently asked questions

Always ensure that you get your boiler serviced at least once a year. It doesn't take too long and will save you time and money in the long run. 

To book an annual boiler service with BOXT, you will need to sign up for one of our home cover plans. Once you’ve signed up, you will be able to leave the rest to us. We’ll contact you around one month before your boiler is due a service and provide you with a few dates.

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