Category - Boilers
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Will Scholfield, Engineer

31 Jan : Updated 6 Dec ● 11 min read

What does a boiler service include?

A boiler can be one of the most expensive appliances in the home, and many households don't realise their reliance on it until something goes wrong. Just like any appliance, a boiler can get damaged if any underlying issues go undetected or ignored.

A boiler service is the best way to make sure your boiler is working exactly as it should and prevent any future breakdowns from taking place.

In this guide, we'll cover everything you need to know about getting an annual boiler service, from what a boiler service includes, to the importance of booking this service every 12 months.

What is a boiler service?

A boiler service is when a heating engineer attends your home to make sure that your boiler is working exactly as it should. The engineer will complete a number of checks, including the boiler itself, the flue, gas pressure and combustion within the appliance - but we're going to take a closer look at what happens during a boiler service further on in this guide.

A boiler service should be part and parcel of your household's outgoings every year. Without it, you run the risk of voiding your boiler warranty and reducing the lifespan of your boiler.

However, it's important that a boiler service is only performed by a qualified Gas Safe engineer.

DO NOT attempt to service your boiler or make any repairs yourself. You could not only put your family in danger but also run the risk of voiding your boiler warranty.

What is included in a boiler service?

It's always good to know what your boiler service includes so that you can cross-reference these on the report your heating engineer gives you.

There are several steps that make up a typical boiler service, which may vary slightly depending on the engineer. However, they all follow a similar boiler service checklist.

1. Visual inspection

The first stage of a boiler service is a visual inspection.

Your Gas Safe engineer will take a visual check of your boiler from the outside. Engineers are qualified to inspect the boiler safely and efficiently, so they will know exactly what to look out for during a visual inspection.

During this inspection, you may see the engineer looking for any leaks or corrosive damage that may have occurred since their last visit. They will also check the boiler flame to see if it looks normal.

2. Boiler casing removal

After the Gas Safe Registered engineer has completed the visual inspection, they'll then check the internal workings of the boiler. This requires them to remove the boiler's casing. This casing protects all the main components within the boiler from damage and will allow the engineer to check the internal components and clean the inside of the boiler where necessary.

They will check the burner, the heat exchanger, and other components which are critical for the boiler’s performance. 

3. Boiler checks

A boiler service includes ticking off lots of different tests. These include:

Flue check

This is where the engineer will check to see if there are any obstructions within the flue terminals. They will also ensure that the boiler flue is safely fitted and that any dangerous gases are discharging effectively.

It's a key boiler component to check, and only a Gas Safe Registered engineer has the qualifications to do this check properly.

Gas pressure check

A gas pressure check is essential, especially as high or low boiler pressure can be problematic for your boiler's performance and lifespan. Your taps and radiators rely on the gas pressure to be at the right levels, otherwise, they won't heat up properly.

To make sure you always have sufficient heating and hot water in your home, the Gas Safe registered engineer will check the boiler's gas pressure.

Flue gas analyser check

The engineer will reassemble the boiler then adjust the boiler to maximum and sometimes minimum output for a short periods of time at which points they will use their flue gas analyser to check combustion and make sure your boiler is burning the gas it is using safely.

The boiler fires up properly

The heating engineer will check that the boiler starts up as it should and that there are no faults.

Checking of integral safety devices

All boilers have some sort of safety device/s built into them - the engineer will also test these to make sure they are all operating as they should.

4. Boiler service report

Once all the relevant boiler and system checks are completed, the Gas Safe engineer will issue a report or boiler service certificate. This is when they will highlight any potential problems or issues that need addressing and what is required to fix or amend these boiler problems.

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Why is a boiler service so important?

Sure - it's not illegal to skip your boiler service (unless you’re a landlord, in which case it’s a legal requirement to get all gas appliances serviced annually). But not keeping up to date with your annual boiler services can put you and your family at risk - not to mention financially out of pocket - if something goes wrong that a service could have prevented.

If any problems do occur and you’ve missed an annual boiler service, your insurance company may be hesitant to pay out.

Here are a few reasons you should be booking your annual boiler service.

1. Keep your family safe

Safety is the most important factor for households of any size. A boiler service is key to keeping your family safe from carbon monoxide poisoning and any potential appliance safety issues. The fitting of an approved carbon monoxide alarm is also highly recommended as an additional safety measure.

Carbon monoxide is odourless, so you may find yourself mistaking the symptoms for another illness. These symptoms include headaches, nausea, dizziness, and breathlessness.

During a gas boiler service a qualified engineer will be able to make sure your boiler is not going to have issues where it either produces or leaks carbon monoxide into any area within your home that would cause harm.

2. Prevent potential boiler breakdowns

Preventing breakdowns is essential because boiler repairs can be very costly. When you have an annual boiler service, engineers can catch problems early on that you didn't even realise that you had. Catching the problem early will prevent it from getting any worse.

3. Maintain your boiler warranty

Did you know that not getting a boiler serviced for over a year can void your boiler's manufacturer warranty or guarantee?

If your boiler is still covered under warranty or guarantee, you'll need to make sure you get your boiler serviced annually just in case you ever need to claim.

If you attempt to claim on your boiler warranty and the manufacturer discovers that you haven't kept up with your annual boiler servicing, you'll likely have to pay for the repairs out of your own pocket.

If you’re not sure whether your boiler is still under warranty, contact the manufacturer or take a look at our guide.

4. Ensures maximum boiler efficiency

Over time, boiler efficiency drops. Debris builds up within the system, which can cause blockages and damage. If this debris isn't flushed out, this can lead to long-term damage that can harm the efficiency of your boiler.

A Gas Safe registered heating engineer can detect any build-up in the central heating system and perform a system flush when required to keep your boiler working in tip-top condition.

5. Save money on costly repairs

Annual boiler servicing will likely save you money in the long run. Many will see the upfront costs of boiler services as not worthwhile, but they can help fix problems for less than what you would pay if you simply ignored any issues.

Ultimately, if you don't get your boiler serviced, you won't know whether or not your boiler is safe and in good working condition. The outcome of ignoring your annual boiler service will likely be more expensive than if you maintained your routine checks.

Boiler repairs and new boilers can cost hundreds or even thousands of pounds, so it's worth paying for a boiler service every 12 months to prevent these potentially costly repairs.

6. Reduce your energy bills

Getting an annual boiler service can help you to save money on your energy bills. Typically, problems with boilers can directly impact your energy bill costs, whether that's a fault with the pressure or a boiler leak.

A boiler service will improve efficiency so that your boiler wastes less energy, meaning you'll only be spending what you need on your heating bills.

Signs your boiler needs servicing

Boilers can last much longer than many people realise: up to 15 years! But boilers that last this long are usually well-maintained. If you want a long-lasting boiler, it's a good idea to keep up with your annual services.

So what are some of the tell-tale signs that your boiler requires a service?

1. The pilot light turned off (on older appliances)

Pilot lights are usually featured on older boilers, so your new boiler probably won’t have a pilot light.

However, if your boiler has a pilot light that has turned off or keeps turning off, this is a sign that the boiler isn't working as it should.

The pilot light acts as the ignition for the boiler, a key function of the appliance.

If the pilot light is burning with a yellow flame, this indicates a carbon monoxide leak.

2. You hear unusual noises

When your boiler is in operation, you'll probably hear a sound that eventually fades into the background. This is entirely normal and nothing to worry about.

However, if your boiler is making a noise that isn’t fading, this is a sign that your boiler probably isn't working as it should.

Strange bangs and sounds could all signify the wear and tear that a boiler sometimes encounters as it gets older.

3. The previous service was more than one year ago

If your boiler hasn't had its annual service yet, we have already mentioned that your warranty may be at risk of becoming void. Not only that, but in the space of just 12 months, issues with your boiler can crop up without you knowing.

It's good to get routine checks within a year of your previous boiler service to keep your boiler running as it should.

4. You smell an unusual odour

Unusual odours coming from your boiler are a tell-tale sign that the gas in your boiler may be leaking or there may be other issues.

You may notice dark marks around the boiler's casing, which is a sign that you have a leak. Even though carbon monoxide is odourless, there could be an unusual odour coming from your boiler when there's a leak.

It's vital that you keep your home gas safe. If you do suspect a gas or carbon monoxide leak, turn off the gas supply, open the windows and leave the property immediately.

If anyone is showing symptoms of carbon monoxide poisoning, take them outside and call 999 for an ambulance.

Call the 24-hour Gas Emergency Number on 0800 111 999, and don't return to your house until the leak has been identified and rectified by a Gas Safe registered engineer.

5. Inefficient performance

When the boiler is running, check the heating system around your home.

Are the hot water taps delivering hot water quickly and consistently? Are the radiators hot, or are they tepid?

Chances are, if the boiler isn't working correctly, then it's not going to be performing as it should and providing your home with the heating and hot water it requires.

How often should a boiler be serviced?

Oil and gas boilers should be serviced within 12 months of the previous service. Even if you don't spot any signs of damage or wear and tear, it's best practice to have your boiler checked every year just in case.

Regular maintenance will help to lengthen the life of your boiler, and keeping a watchful eye over your boiler is always a smart habit.

Check out our complete guide on how often your boiler should be serviced.

Gas boiler service

Only an authorised and regulated Gas Safe Registered engineer should conduct a gas boiler service.

When inquiring about a gas boiler service with your heating engineer, they'll check that your home has a gas boiler and will probably want to know the boiler brand too.

Before the Gas Safe registered engineer enters your home to perform the boiler service, make sure to check their ID card to ensure they're a qualified engineer.

Oil boiler service

An oil boiler service needs to be done by an OFTEC engineer. OFTEC consists of a register of technicians from businesses specialising in oil, solid fuel, and renewable heating.

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