How long does a boiler service take?

The boiler is an essential part of any home. We rely on our boilers to heat our homes and water throughout the entire year, but they become especially important in the cold winter months. 

The general advice is to service a boiler once a year. This is required to keep newer boilers under warranty. 

The cost of servicing a boiler is certainly less than the cost of replacing expensive boiler parts or, in the worst case, replacing a broken boiler. 

A boiler service costs around £50 to £100, which works out at just £1 to £2 or so per week - an amount definitely worth spending to prevent your boiler from breaking! Moreover, a well-serviced boiler will run more efficiently and can save money on your energy bills. 

So, how long does a boiler service take?

How long does it take to service a gas boiler?

Gas boilers are the most common type of boilers in the UK. If you live on the mains gas grid, you almost certainly have a gas boiler. 

A typical gas boiler service will take 30 minutes to 1 hour and 30 minutes. 

It’s possible to service a near-brand-new boiler in just 20 minutes, especially if it’s a newly installed combi or system boiler. There are three main types of gas boilers: 

  • Traditional or conventional boilers 
  • Combi boilers 
  • System boilers 

Combi boilers are more modern, providing hot water and heating from the same unit. They’re typically installed in smaller one-bathroom homes and flats but rarely in larger homes with more than one bathroom. Combi boilers are pretty simple and easy to service. 

Boiler Controls
Above: Combi boiler panel

System boilers are also fairly modern and feature a separate water tank, ideal for homes with more than one bathroom. For example, you might have a system boiler if you live in a 2-bathroom+ semi-detached or detached house built since 2000. System boilers are generally more powerful than combi boilers, with more components to check and test. 

Then, we have conventional boilers that feature a cold water feed in the loft. These remain the most common type of boiler for houses. 

Older conventional boilers often require more intensive services, especially if they’re 15 years or old. However, many conventional boilers in the UK are now over 30 years old. This might mean the service takes slightly longer compared to near-new combi and system boilers. 

Servicing Boiler
Above: Repairing a conventional boiler 

How long does it take to service an oil boiler?

Oil boilers are popular for rural and off-grid properties that aren’t on the gas grid. 

Like gas boilers, the general advice is to get your oil boiler serviced once a year. Services should be performed by an OFTEC engineer, a different organisation than Gas Safe who regulate gas boilers. 

They’re frequently used to support other renewable energy sources and are generally as efficient or more efficient than gas boilers. Oil boilers work similarly to gas boilers, except they use liquid fuel rather than gas (heating oil or kerosene). 

Oil boilers are slightly more complex than gas boilers and take a bit longer to serve as a result. 

You can expect an oil boiler service to take 1 to 2 hours. 

How long should it take to service a combi boiler?

As noted, combi boilers are a newer type of boiler that provides heating and hot water from the same unit without the need for any additional water tanks. They’re extremely common in flats and are becoming increasingly common in small houses. 

Many combi boilers installed today are still quite new, so services may only take 30-minutes, but 1 hour is a more typical estimate.

If your new combi boiler is under warranty, then make sure you service it as per the manufacturer’s guidance, or else you might void your warranty. 

How long does it take to service a Vaillant boiler?

Vaillant is a well-known, reputable boiler brand that recommends yearly boiler services. This is usually a condition of their warranty. 

Vaillant says an average service will take around 1-hour

A typical service includes checking the boiler and heating controls, testing safety devices and boiler sensors, inspecting the combustion chamber and expansion vessel pressure and checking consumption and flue performance. 

How long does it take to service a Worcester Bosch boiler?

Worcester Bosch is a well-known, reputable boiler brand that recommends yearly boiler services. This is usually a condition of their warranty. 

Like any other boiler service, a Worcester Bosch service should take at least 30-minutes, but 1-hour is a more typical estimate. 

How long does it take to service a Baxi boiler?

Baxi is a well-known, reputable boiler brand that also recommends yearly boiler services. This is often a condition of their warranty. 

Baxi says an average service will take around 30-minutes.

A typical Baxi service includes flue and combustion analysis, checking electrical connections, seals, electrodes, and safety devices and inspecting condensate pipes and water and gas pipework

How long does it take to service a Viessmann boiler?

Viessmann is a well-known, reputable boiler brand that recommends yearly boiler services. 

Viessmann says an average service will take around 1-hour

What should happen during a service?

Boiler services vary depending on the make, model and type of boiler, its age, and many other factors. For example, older boilers generally require more intensive services, while newer boilers might just need a quick check that takes around 20 to 30-minutes. 

A typical boiler service includes: 

1: Visual inspection 

The engineer will first inspect the boiler’s overall appearance to discover any leaks, rust or superficial faults. The proximity of the boiler to combustible materials, corrosion and signs of overheating or stress will all be checked. 

2: Flue and gas analysis 

The flue is analysed for its performance and integrity. This involves using a flue gas analyser (FGA). Engineers will also check the gas rate, which measures how much gas the boiler uses. 

This should remain in the manufacturer’s guidance for the boiler to work efficiently. If the gas rate is incorrect, the engineer will diagnose the issue and correct it to improve boiler efficiency. 

3: Cleaning

Electrical connections, seals, electrodes and other parts are disassembled and cleaned. Corrosion and mineral build-up are removed, and components are replaced if necessary. 

4: Diagnostics

The engineer will perform various diagnostic checks to analyse boiler performance and inspect various parts, including:

  • General boiler operation and controls 
  • Condensate trap and pipe
  • Electrical connections
  • Flue analysis
  • Gas flow and pressure 
  • Heating controls and thermostat
  • Pilot light
  • Safety devices
  • Seals
Testing a boiler
Above: Boiler diagnostics 

5: Record the service

The engineer will provide a service report and submit the service to the manufacturer if required (e.g. to keep a boiler under warranty). 

Make sure that you keep a record of boiler services and repairs, as this will be an advantage if your boiler breaks under warranty or if you sell your house. 

Engineer servicing  a boiler
Above: The engineer will produce a service report

Summary: How long does a boiler service take?

There’s no one-size-fits-all approach to servicing boilers - each service differs slightly from the next. 

Boiler services take 30-minutes to 1 hour for most gas boilers. Newer boilers can be serviced in just 30-minutes. Gas boilers take a little longer to service, around 1 hour to 2 hours. 

Servicing is well worth it in the long run as it helps boilers run smoothly and safely. In addition, regular servicing will boost boiler efficiency, which will lower your energy bills. 

As energy bills rise, the impact of a regular boiler service is bigger than ever - so make sure to book your boiler service for this year!