Boiler Service Checklist & What Does a Boiler Service Include?

James Elston
Written by James Elston
Updated on 19th March 2024
Posted on 1st March 2024
Topic: Boiler Advice

What does boiler service include? A typical service encompasses essential evaluations and adjustments to ensure your heating system’s efficiency and safety.

This includes operational checks, safety inspections, component cleaning, and system testing.

Each step is designed to address potential issues and maintain prime performance, much like a regular check-up for your vehicle. Our article details the precise actions taken during a thorough boiler service.

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Boiler Service Checklist Overview

  • Annual boiler servicing includes comprehensive checks, tests, cleaning, and operational and safety assessments to ensure efficiency, safety, and cost savings over time. It can prevent larger issues from developing, maintain system performance, and preserve the warranty.
  • A boiler service encompasses visual inspections, checking and cleaning internal components like the heat exchanger and combustion chamber, fine-tuning gas pressure and flow, and ensuring the flue and ventilation systems are adequate and safe.
  • Getting your boiler serviced often is essential for maintaining the boiler’s warranty, preventing costly breakdowns, and avoiding safety hazards. The service should be documented for proof of maintenance, with costs varying by boiler type and age, and optional boiler cover plans available for financial protection.

Our Expert Gas Safe Engineer Says:

A boiler service may seem like an unnecessary expense, however, it can stop any nasty surprises during the super cold months just when you need your boiler the most. You should always schedule your boiler service during summer.

James Murfin

Gas Safe Registered Heating Engineer

What is Included in a Comprehensive Gas Boiler Service?

A comprehensive boiler service include:

  • A thorough examination of your household’s boiler
  • Enhancing its efficiency and safety through a series of checks, tests, and cleaning procedures
  • Operational checks to assess if the boiler operates correctly and verify that boiler temperature controls are functioning properly
  • A basic visual inspection to identify any obvious signs of damage, faults, or dirt accumulation

Regular servicing is not just a recommendation; it’s a necessity to maintain your central heating system all year long. Think of it as a health check-up for your boiler, designed to:

  • Nip small problems in the bud before they morph into larger, more expensive issues over time
  • Reduce the risk of breakdowns
  • Improve performance
  • Ensure the validity of the boiler warranty
  • Ultimately lead to cost savings over time.

In essence, an annual boiler service is a minimal investment for the peace of mind it provides.

Visual Inspection and System Overview

The first step in a boiler service is a comprehensive visual inspection to check for signs of leaks, corrosion, or other indicators of wear and tear.

Trained heating engineers assess the boiler’s exterior and components for visible damage or wear, including checking for leaks or corrosion. This initial visual inspection is standard practice to ensure everything looks in order before proceeding with further checks.

Operational Checks and Efficiency Testing

Once the visual inspection is complete, operational checks and efficiency testing take center stage. This involves:

  • Reviewing and adjusting gas pressure and flow settings as needed
  • Using flue gas analysers to properly check and sign off on the boiler flue’s integrity as part of the heating system service
  • Inspecting the flue terminals to ensure they are not blocked and have been sealed correctly

These steps are vital to ensure the proper functioning of the heating system.

These checks, along with testing the boiler and system controls, including temperature controls, ensure they are functioning correctly.

Safety First: Carbon Monoxide and Gas Leak Detection

No boiler service is complete without a focus on safety. Safety checks during a boiler service aim to identify any leaks of water or gas that could threaten household safety, including unusual smells and dark marks indicative of potential gas leaks.

This includes checking safety devices, such as gas safety valves, to ensure they are functioning properly and can prevent dangerous gas leaks and carbon monoxide incidents.

An inspection of the boiler flue is also carried out to confirm its effectiveness in channelling exhaust gases out of the house, which is a key factor in preventing carbon monoxide buildup inside the dwelling. Ultimately, the safety of your home’s heating system is of utmost importance.

Servicing Boiler Components and Cleanliness

Now, let’s delve under the hood to explore the boiler’s internal components and cleanliness. The cleaning process during a boiler service involves removing, inspecting, and cleaning major components such as the spark probe, main injector, and heat exchanger.

Regular boiler servicing helps prevent a build-up of dust, soot, or debris, ensuring that the boiler operates as energy-efficient as possible.

Here are the key benefits of regular boiler servicing:

  • Prevents build-up of dust, soot, or debris
  • Ensures energy-efficient operation
  • Identifies issues early on
  • Prevents future breakdowns
  • Preserves warranty (adhering to manufacturer’s instructions by a Gas Safe registered engineer)

By following these guidelines, you can ensure that your boiler remains in good working condition and avoid any unnecessary problems.

Heat Exchanger Health Check

One of the major components that requires a thorough check is the heat exchanger. This part is checked for soot or corrosion during a boiler service, as these can reduce its efficiency and may cause it to break down.

To maintain optimal performance, the heat exchanger should be cleaned of any scale and soot buildup, ensuring maximum heat transfer and efficiency.

Proper seals must also be checked when reassembling the heat exchanger post-cleaning to prevent any potential leaks.

Clearing the Combustion Chamber

Next comes the combustion chamber. The boiler service includes cleaning the pilot assembly, gas injectors, and spark electrodes to ensure the combustion chamber functions properly.

Also, the pilot light is assessed, especially in older boilers, to ensure the boiler is burning fuel properly.

Maintenance of the combustion chamber includes cleaning or replacing the burner nozzles and electrodes to prevent incomplete combustion and soot deposits.

Seals and Joints – No Leaks Allowed

Lastly, seal integrity and joint security are pivotal in preventing leaks and ensuring the gas boilers operate safely without gas emissions.

During maintenance, engineers specifically test gas joints that have been disturbed to confirm there are no leaks and that all seals hold up to the standards required for operation.

Important read – Boiler not serviced every year dangers

The Importance of Correct Gas Pressure and Flow

Having the correct gas pressure in a boiler is key for its safe and efficient functioning. Incorrect pressure can cause performance issues and safety hazards.

For instance, high gas pressure can lead to strain on boiler components, expedite wear, and potentially cause dangerous gas leaks. On the other hand, boiler pressure that falls within the optimal range of 1 and 2 bar is best for the boiler’s optimal performance.

During a boiler service, the pressure is checked across three points: the boiler, the inlet burner, and the gas meter to ensure the entire system is functioning optimally.

The boiler service report documents the gas pressure check to confirm that the boiler has been verified to have optimal gas pressure.

Fine-Tuning Gas Pressure

Fine-tuning the gas pressure involves checking and adjusting pressure levels for optimal performance and safety.

Low gas pressure can lead to incomplete combustion, resulting in the production of carbon monoxide and increased energy bills, as well as the potential for costly repairs.

Regular servicing by a qualified engineer is recommended to maintain the gas pressure at the correct level for optimal boiler performance and safety.

Flue and Ventilation Adequacy

Flue and ventilation adequacy checks are carried out to ensure proper exhaust and air supply, preventing carbon monoxide buildup.

The flue is connected to an internal fan designed to expel combustion products, and the boiler’s operation is contingent on the flue’s functionality, reinforcing safety.

Documentation and Peace of Mind

After a boiler service, you should receive a detailed report documenting all the checks performed. If issues are identified, the engineer will discuss recommendations for boiler repairs with the homeowner, and immediate actions may be taken if agreed upon.

In rental properties, a Gas Safety Certificate is a mandatory record that needs to be completed by a registered engineer after a boiler service. Not only does this serve as proof of service, but it also helps in maintaining your boiler warranty intact.

Your Boiler Service Report

The boiler service report includes:

  • Detailed information and confirmation of all the checks performed during the service
  • Advice on any necessary service needs
  • Documentation of any working faults detected when the boiler is fired up to help identify any immediate or future issues.

This report serves as a tool for homeowners to track the ongoing performance of their boiler, potentially flagging issues before they escalate into major boiler repairs.

Boiler Service Certificate: Proof of Service

A boiler service certificate serves as proof that the boiler has been checked and serviced by a qualified engineer, which ensures the boiler operates safely and efficiently. The certificate should include:

  • The engineer’s name
  • Company information
  • Gas Safe number
  • List of any problems encountered with recommendations for maintenance

This documentation is your evidence for maintaining the boiler’s warranty validity and compliance.

Furthermore, homeowners are recommended to retain the service certificate for future purposes like property sale, as it can serve as a record of proper maintenance.

Keeping Your Boiler Warranty Intact

Annual boiler servicing by a qualified professional is a common requirement set by manufacturers to keep the warranty valid.

Keeping a meticulous record of boiler services is important as it is necessary for claiming the warranty, and skipping annual service or not using a qualified professional can void the warranty.

Warranty Requirements

Most boiler manufacturers require at least one annual service as a condition of the boiler’s warranty. Some manufacturers even offer a grace period around the servicing anniversary for performing the needed annual service.

Maintaining the boiler in accordance with the manufacturer’s maintenance instructions is essential to keep the warranty valid.

Manufacturer’s Instructions Compliance

Adhering to the manufacturer’s instructions is crucial for the longevity and efficiency of your boiler.

An annual boiler service should comply with the manufacturer’s guidelines, which are outlined in the boiler’s operating manual.

Detailed records of servicing and maintenance, in line with the manufacturer’s instructions, are critical to uphold the warranty and should be kept up to date and available on-site to substantiate warranty claims.

Some manufacturers may stipulate that their boilers be fitted by specifically trained or accredited installers to qualify for extended warranty coverage.

How much does a boiler service cost?

In the long term, routine boiler servicing can also lead to financial savings.

A full boiler service is estimated to cost between £85 to £100, while a one-off fee boiler service can cost from £65 to £100. The cost of a boiler service can be influenced by the age of the boiler, its type (e.g., oil), and the availability of replacement parts.

However, consider this an investment in your boiler’s future. Regular maintenance can prevent costly breakdowns and extend the life of your boiler, saving you money in the long run.

Breakdown of Service Costs

The cost of boiler service can vary depending on several factors. The gas boiler service cost for servicing a gas boiler is between £80 and £120, an oil boiler service typically ranges from £75 to £110, and a combi boiler service averages around £90.

Commercial boilers with an output of 40 kW or under generally have a minimum call-out fee of approximately £95.

Landlord boiler servicing costs more as they are required to obtain a Gas Safety Certificate at an additional cost ranging from £120 to £150 for a single boiler and one gas appliances check.

Boiler Cover Options

To safeguard against unexpected repair costs, you might want to consider a boiler cover plan. Just as you have insurance for your home or car, boiler cover is an insurance plan that covers the costs of services and repairs, including labour costs and any new parts required.

Boiler cover plans come in two main categories: boiler-only packages and full system packages, with some options extending to drains and external factors.

Choosing the right boiler cover requires weighing the costs against potential risks, with more comprehensive plans potentially better for older systems.

Timing and Frequency: When to Service Your Boiler

Scheduling a boiler service in the summer months, as opposed to winter, is recommended. The warmer months are suggested for boiler servicing to allow time for repairs before winter and to minimise household disruption.

Setting a reminder to book the next annual boiler service is a recommended practice to ensure regular maintenance. Regular servicing prevents unexpected breakdowns and maintains the efficient performance of your boiler.

Booking a Service

The timing of your boiler’s service can have a significant impact on its efficiency. Scheduling your yearly boiler service during off-peak seasons can provide ample time for repairs and ensure your boiler is ready for the winter demand.

The summer months are recommended for boiler servicing as it allows any arising issues to be addressed promptly before the colder weather sets in, ensuring your heating system is reliable when needed most. Servicing boilers after a period of dormancy during warmer seasons is recommended to confirm they are fully operational ahead of the increased usage in colder periods.

Scheduling a service every year

Regular boiler servicing ensures the early identification of potential issues, thereby enhancing safety and maintaining energy efficiency.

Consistent maintenance through annual boiler service prevents unexpected breakdowns, ensuring the heating system remains operational when needed most.

Fewer boiler breakdowns are observed with regular servicing, as this practice involves inspecting and replacing tired components to optimise reliability. To uphold optimal performance and safety, it is recommended that your boiler serviced annually, ensuring that boiler servicing is conducted at least once every year.


So, there you have it! Your boiler requires the same attention to ensure a safe, efficient, and reliable heating system. A comprehensive boiler service includes a thorough visual inspection, operational checks, safety measures, and cleanliness checks of internal components.

Regular servicing, ideally once every year, can help identify and address potential issues early, maintain your boiler’s warranty, and ultimately, save you money in the long run.

Remember, proper maintenance of your boiler is not just about avoiding unexpected breakdowns or costly repairs. It’s about ensuring the comfort and safety of your home.

So, don’t wait until the last minute. Schedule your boiler service today and enjoy the peace of mind that comes with a well-maintained and efficient heating system.

Frequently Asked Questions

Does a boiler service include radiators?

No, a boiler service typically does not include checking the radiators for leaks or corrosion. It is an additional check-up beyond the formal boiler service.

What is involved in boiler maintenance?

Boiler maintenance involves fully inspecting the boiler flue, checking gas pressure and flow, ensuring proper combustion, and cleaning vital internal components such as the spark probe and heat exchanger. Proper maintenance is essential for safety and efficiency.

Does a boiler service include a system flush?

Yes, a boiler service can include a central heating system flush if requested or the heating engineer detects build-up in the central heating system. Regular flushes can help keep your boiler working properly.

How often should I service my boiler?

You should service your boiler at least once every year to ensure optimal performance and safety.

Why is it recommended to service the boiler during the summer months?

It is recommended to service the boiler during the summer months to address any necessary repairs before winter and avoid household disruption.

Written by
James Elston
James Elston Director Of Boiler Central
Posted on: 1st March 2024
Topic: Boiler Advice

James Elston is our resident boiler replacement and heating expert here at Boiler Central. With over 20 years experience in the boiler installation industry, James ensures that he knows everything there is about our Gas Safe boiler installations, energy saving and home heating solutions. This can be from simply procuring the latest best combi boilers, to reviewing and ensuring that Boiler Central maintains the highest standards across our boiler installation company.

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