What Does a Boiler Service Include? Everything You Need to Know

With energy prices rising at an alarming rate and cold snaps becoming increasingly common during the winter months, the last thing you need to be worrying about is your boiler breaking and not being able to heat your home.

To keep your boiler running smoothly and reliably, getting it serviced regularly is vital. But what does a boiler service include, and when do you know it's time to get yours booked?

In this guide, we'll walk you through everything you need to know about gas boiler services so you can make sure your home's central heating system is properly maintained all year long. Keep reading to learn how much a boiler service costs, what a boiler service includes, who can carry out a boiler service, and more.

What to expect from a boiler service

So, you've found yourself a Gas Safe-registered engineer to carry out your boiler's annual service, but what should you expect to happen when they arrive at your home?

Initially, the engineer will likely introduce themselves and show you their Gas Safe ID card as proof that they have the required qualifications. If they don't automatically show this, you should feel perfectly able to ask them before they start working on your boiler.

After introductions, good engineers will then ask you if there have been any recent issues with your boiler or central heating system more generally. They may also offer to put down flooring protection or dust sheets to prevent any dirt or water from falling onto your floors during the servicing.

What does a boiler service include?

When you get your annual gas boiler service, there are a few things that the engineer will do and check for. Your engineer might not follow this boiler service checklist in the exact order detailed below, but that's okay, just as long as they go through all of the necessary steps and provide you with a boiler service certificate proving that your boiler has been serviced.

1. Visual inspection

Once you have shown the engineer your boiler's location within your home, they will start by conducting a visual inspection of the system. This involves looking at the boiler's hot water cylinder, its connecting pipework and the control panel in reference to the manufacturer's instructions.

They will also check whether the fuse rating for your boiler is correct. If the fuse is too high, this leads to dangerous overheating, as it will not break the electrical circuits inside your boiler if a fault means that too much current is passing through.

2. Firing up

If it isn't already running, the engineer will fire up your boiler to make sure it comes on and starts heating water effectively. They will then isolate it using specialist electrical test equipment.

3. Casing removal

Once the engineer has finished with the visual inspection, they will remove the boiler's casing to carry out a thorough check of the insides. When the casing has been removed, the engineer will be looking at a few things, such as:

The main injector

The burner

The spark probe

The heat exchanger

At this point, they will look for any obvious weak points or faults, such as corrosion damage and gas leaks and also check the boiler's flame, known as its pilot light.

4. Flue check

The engineer will check your boiler flue. This is the pipe that leads from your boiler to the exterior of your house. They'll be checking to make sure that the flue pipe is well-fitted and that there are no blockages or obstructions that could be preventing water from flowing through easily.

Note: It's especially important to check a boiler's flue pipe after periods of colder weather, regardless of whether your boiler's annual service is due, as they are prone to freezing over and becoming blocked.

5. Gas pressure checks

A boiler needs to have the correct gas pressure at all times. Without the correct pressure, the water in the taps and radiators won't heat up to the correct level. The engineer will refer to the manufacturer's guidelines and make sure that your boiler system is pressurised correctly.

6. Additional checks

The engineer will make sure that the boiler functions and controls are working sufficiently. They will also check any safety devices to make sure that they are working effectively.

They will also check that the boiler is in an adequately ventilated area. They will also want to be sure that the boiler isn't next to any flammable or combustible materials.

After doing these final checks, your boiler engineer will return everything to your preferred settings using your thermostats or smart controls.

7. Issuing a report

The engineer should keep a record of every test that they run on the boiler, detailing the checks that have been carried out and any faults found. This report is a useful tool for the homeowner because it'll let you know whether anything needs addressing.

When boiler servicing in the future, this document will inform the future engineer about any previous issues and what to look out for this time around.

Why should I get an annual boiler service?

It might seem like more hassle than it's worth, but it's vital to get your boiler serviced at least once a year. For starters, you have to make sure that your central heating system is running safely and effectively, but the importance of boiler servicing goes far beyond this.

Let's look at the main benefits of getting your boiler serviced regularly.

Early detection

Annual boiler servicing allows you to catch any problems early on and before they have a chance to escalate into full-blown system failures.

Spotting the problem early will make the boiler repairs much cheaper than when it's become advanced, as you'll probably only have to replace a part or two as opposed to replacing the whole boiler.

Cheaper energy bills

Making sure that you have your annual boiler service can decrease your energy and heating bills as it will help you ensure that your boiler is working as efficiently as possible. With natural gas prices at record highs, the importance of this for us as homeowners has never been more acute.

Family safety

If a gas boiler isn't running properly, it can produce toxic carbon monoxide gas into the surrounding air. This is odorless and deadly, so it's important that any leaks are spotted right away and dealt with immediately. The worst part is that the range of symptoms of carbon monoxide poisoning can easily be mistaken for something else, so you may be none the wiser until it's too late.

Combine staying on top of your boiler services with installing a carbon monoxide detector in your home, ideally close to where your boiler is located.

Boiler warranty

Skipping your boiler service will void your warranty. This means that any potential issues and repairs won't be covered and could see you landed with a hefty bill for any replacement parts or labour required.

It's the law

If you're a landlord or a landlady, you are required by law to do any annual boiler service. You must also check any other gas appliances that you own.

If you're a homeowner but don't rent your home out to anyone, it's different. You're not law-bound to have an annual boiler service. But, for all the other reasons on the list, it should be high on your list of priorities - even if it doesn't seem essential now, it'll be worthwhile in the long run.

Signs it's time for a boiler service

Signs its time for a boiler service

A boiler that's been well-maintained can last nearly 15 years. Maintaining your boiler means getting your annual boiler services and addressing any problems when you find them.

Your boiler might already be showing signs of issues that you haven't taken note of. Some of the most common boiler problems and signs that it might be time for a service include:

Pilot light issues

Your pilot light works as the ignition for your boiler. So, if the pilot light is off, your boiler is not working. If the pilot light comes on but keeps turning off, that is also a sign that you need to get it serviced.

If your pilot light is on, but you notice that it has a yellow flame, that's a problem. This means that there's a carbon monoxide leak that needs to be addressed immediately. Get an engineer to inspect the boiler as soon as possible and potentially think about staying somewhere else until they do.

Loud noises

When your boiler is working, it can make a sound. Typically, this sound eventually fades into the background. If you hear noises from the boiler that sound odd or new, there might be a problem.

Unusual odours

If you detect an unusual odour coming from the boiler, it might need a boiler service. This means that the gas in the boiler is leaking. If this is the case, you will notice dark marks on the boiler casing. If you notice these dark marks, call an engineer immediately who can come out and assess whether there is a gas leak.

Inefficient performance

If you have the heating turned on and the house is still cold, it might be a boiler problem. If you've already checked your radiators, and they seem to be working fine, the boiler is probably the issue. Your boiler might need a power flush. Call an engineer, and they'll check your boiler and find the issue.

It's been a year

If it's been a year (or more) since your last boiler service, it's time for another - even if you don't notice any problems with your boiler. Remember that failing to get your boiler serviced according to the manufacturer's instructions can mean that your warranty becomes invalid.

How much does a boiler service cost?

Boiler services don't typically cost too much and will always be cheaper than having to replace your entire boiler should it break due to being poorly maintained. The cost depends on a few factors, including

The boiler type

Your location

The boiler fuel

Manufacturer and model

Location of the boiler in the house

The engineer's rates

Boiler services can be paid for in two different ways - as a one-off fee or through an insurance package.

A one-off fee boiler service can cost from £65 to £100.

Boiler cover can cost from £180 to £300 per year.

Whilst the latter option is more expensive, it's the best route for anyone whose warranty has expired or become void. Boiler cover will also provide you with complete peace of mind that the cost of any replacements will be taken care of in the event of a breakdown.

How long does a boiler service take?

How long a boiler service lasts will vary by brand and model. With that in mind, check with your chosen engineer to make sure that they can perform a boiler service on your particular brand and model.

But typically, a boiler service should take between thirty minutes and an hour. The boiler service can take longer than that if the engineer runs into any problems that need to be addressed.

How do I find a boiler engineer for my yearly boiler service?

How to find a boiler engineer

If you have a gas boiler or other gas appliances, your engineer needs to be Gas Safe certified. This is a national register of professionals who have the qualifications and accreditation's needed to carry out boiler services and repairs safely. You can easily find a Gas Safe-registered engineer in your area online.

For extra advice on information on fitting, maintaining, and servicing your boiler, you can check out our boiler guides.


When should I get my boiler serviced?

As we've previously noted, you should get your boiler inspected by an engineer any time you notice a problem. If left unchecked, small faults can escalate into serious issues, so it's always best to act promptly to avoid being stuck without central heating and needing to pay for more complex fixes further down the line.

When scheduling your annual boiler servicing, you might want to aim for summertime. This is a period when you aren't as reliant on your boiler and when you may find it easier to get an engineer. Getting your boiler serviced in the summer months will also mean that you can go into winter confident that your boiler is up to the task of heating your home come the winter.

Can I service my boiler myself?

Your boiler should only be serviced by a Gas Safe-registered engineer. They will have the qualifications and training needed to perform the service properly and safely, making sure that it is checked thoroughly for any potential faults or errors.

It's recommended that you get your boiler serviced annually, or your boiler's warranty could end up becoming void. In rental properties, every landlord is required, by law, to keep records of gas boiler services. As in private properties, this record must be a Gas Safety Certificate completed by a registered engineer.

If possible, don't wait until the last minute to get your boiler serviced, as it could be a number of weeks before an accredited engineer is available to come out to your home and perform all the necessary checks.