Quick answer
Most gas and LPG boilers should be serviced once every 12 months by a Gas Safe registered engineer. Boiler manufacturers usually make an annual service a condition of the warranty, and HSE recommends annual servicing where no manufacturer instructions exist. A yearly service checks the boiler is burning safely, efficiently and is free of developing faults.
Why once a year is the standard
There is no law that makes a homeowner service their own boiler, but almost every manufacturer's instructions say it should be serviced every year. Most boiler warranties are only valid if you can show a service record for each year, so missing one can leave you paying for a repair that would otherwise have been covered.
The Health and Safety Executive (HSE) says gas appliances should be serviced in line with the manufacturer's instructions, and if those are not available, annually unless a Gas Safe registered engineer advises otherwise. In practice, 12 months is the interval to plan around.
What happens during a boiler service
A service is a hands-on inspection of the boiler, not just a visual check. Exactly what is done depends on the make and model, but it usually includes:
- Checking the boiler is safely installed and that the flue is correctly fitted, supported and terminating in a safe place.
- Measuring the flue gases with a combustion analyser to confirm the boiler is burning cleanly.
- Checking the gas pressure and gas rate against the manufacturer's figures.
- Removing the case, inspecting and cleaning key components where the manufacturer requires it, and checking seals.
- Checking the condensate pipe, system pressure, controls and safety devices.
- Recording the results and any advice on the service record or in the benchmark logbook.
Signs your boiler needs attention before its next service
Do not wait for the annual visit if you notice any of these:
- Yellow or orange flames on an older open-flame appliance, or soot staining around the boiler or flue.
- Pressure dropping repeatedly (see our guide on why a boiler loses pressure).
- New banging, whistling or gurgling noises.
- Fault codes, lockouts or the boiler cutting out.
- A carbon monoxide alarm sounding. If that happens, turn the appliance off, open windows, get fresh air and call the National Gas Emergency Service on 0800 111 999.
Landlords: servicing versus the gas safety check
If you rent out a property, the rules are stricter. The Gas Safety (Installation and Use) Regulations 1998 require landlords to have every gas appliance and flue they provide checked for safety every 12 months by a Gas Safe registered engineer, and to keep appliances maintained in a safe condition. HSE points out that an annual service is not automatically the same thing as the safety check, and a safety check on its own is not full maintenance. Many landlords book both on the same visit. Our guide to the landlord gas safety certificate (CP12) explains the rules in detail.
Does a new boiler need servicing in its first year?
Yes. Most manufacturers ask for the first service within 12 months of installation to keep the warranty valid. Put a reminder in your calendar on the installation date so it is not missed.
What about older boilers?
Older boilers benefit from servicing at least as much as new ones, because parts wear and efficiency drops over time. If a boiler is regularly failing or parts are hard to source, your engineer can talk you through whether repair or replacement makes more sense.
CombiCert in Telford
CombiCert Ltd is a Gas Safe registered (621146) gas and heating company based at The Old School House, Park Lane, Telford TF3 4TG, working across Telford and Shropshire for homes and businesses. We are open Monday to Saturday, 08:00 to 19:45 (closed Sunday).
Boiler service from £90 + VAT (£108 inc VAT). Filters, flushes and thermostats are paid add-ons.
See Boiler service Telford for details, or call or WhatsApp 07393 220694, or email hello@combicert.co.uk.
Frequently asked questions
Is a boiler service a legal requirement for homeowners?
No. Homeowners are not legally required to service their own boiler. However, manufacturers recommend an annual service, most boiler warranties depend on it, and HSE advises annual servicing where there are no manufacturer instructions. Landlords are different: they must have an annual gas safety check on appliances they provide to tenants.
Can I go longer than 12 months between services?
You can, but it is not recommended. Going longer may breach the terms of your boiler warranty and means developing faults or unsafe combustion may go unnoticed. Booking the service around the same date each year is the simplest way to keep the warranty valid and the boiler running safely.
How long does a boiler service take?
A typical domestic boiler service takes around 30 to 60 minutes, depending on the make, model and how accessible the boiler is. It can take longer if the engineer finds a fault, needs to clean components the manufacturer specifies, or the system needs extra work such as repressurising or clearing a condensate pipe.
Who is allowed to service a gas boiler?
Only an engineer on the Gas Safe Register may legally work on gas boilers and appliances in the UK. Ask to see their Gas Safe ID card and check the back for the types of gas work they are qualified to do. You can also check any engineer on the Gas Safe Register website.
Does an LPG boiler need servicing as often as a mains gas one?
Yes. LPG boilers should also be serviced every 12 months by a Gas Safe registered engineer who is qualified for LPG work. LPG is heavier than air and behaves differently if it leaks, so annual checks of the boiler, its controls and its gas supply are just as important as on natural gas.
This guide is general information, not a substitute for an on-site assessment by a Gas Safe registered engineer. If you smell gas, call 0800 111 999.