Blog
What happens during an annual boiler service?
What gets checked, why your warranty probably depends on it, and what you should have in your hand at the end.
An annual boiler service is one of those jobs that is easy to put off when the boiler seems fine. But the service is where small problems get caught before they turn into a cold house in January, and for most newer boilers it is also what keeps the warranty valid. Here is what actually happens during the visit.
Why a yearly service matters
The Energy Saving Trust recommends having a boiler serviced every year by a Gas Safe registered engineer. There are three good reasons:
- Safety. A gas boiler that is not burning properly can produce carbon monoxide, which you cannot see or smell.
- Warranty. Most manufacturers' warranties require an annual service, and the service record is the first thing asked for if you need to claim.
- Reliability and running costs. Pressure that keeps dropping, a pump working harder than it should or a blocked filter are not emergencies on the day they start, but they usually become one.
What happens during the service
The details vary with the make and model, and the manufacturer's service instructions set out what should be done. A typical service includes:
Visual checks
The boiler, flue and pipework are checked for signs of leaks, corrosion, damage or poor fixing. The flue terminal outside is checked to make sure nothing is blocking it and that it is still a safe distance from windows and openings.
Combustion and gas checks
The engineer uses a flue gas analyser to check the boiler is burning gas cleanly and efficiently. The gas pressure and the rate the boiler is burning gas are checked against the manufacturer's figures.
Inside the boiler
Where the manufacturer calls for it, the case comes off and parts such as the burner, heat exchanger and condensate trap are inspected and cleaned. Seals are checked, because a poor seal on the combustion chamber is a safety issue.
System checks
The system pressure and the expansion vessel charge are checked, the magnetic filter is cleaned if one is fitted, and the controls and thermostat are tested to make sure the boiler responds properly.
Safety devices
The safety devices built into the boiler are tested to make sure they shut it down if something goes wrong.
How long does a boiler service take?
A routine service on a boiler in good condition usually takes around an hour. It can take longer if the boiler needs a deeper clean, the filter is full of sludge or something needs attention. If a part is needed, you should be told what it is, why, and what it will cost before any work goes ahead.
The paperwork you should get
At the end you should get a record of the service. That is often the service section of the Benchmark checklist in the boiler manual, or a digital or paper service record. Keep it with the boiler paperwork. It is what you will need for a warranty claim, and buyers sometimes ask for it when you sell.
For rented property, a landlord gas safety record is a separate document with its own legal requirements. The two can usually be done at the same visit. There is more in landlord gas safety checks explained.
How to prepare for the visit
- Clear access to the boiler, especially if it is in a packed cupboard.
- Have the boiler manual handy if you have it.
- Make a note of anything odd: noises, pressure drops, radiators that do not heat properly. A service is a good time to mention them. If the pressure has been dropping, why a boiler keeps losing pressure explains the likely causes.
Why autumn is a good time to book
A service in autumn means any problems are found before the boiler is working hardest. It also avoids the first cold snap, when breakdowns peak and everyone wants an engineer on the same day.
Boiler servicing in Hythe and Ashford
I service and repair boilers across Hythe, Ashford and the surrounding villages, with what was found explained in plain terms, including what can wait and what cannot. See boiler servicing and repairs to book, landlord and rental work for let properties, or boiler installation if the boiler is past the point where repairs make sense.
Common questions
How often should a boiler be serviced?
Once a year. Most manufacturer warranties require it, and the Energy Saving Trust recommends an annual service by a Gas Safe registered engineer.
How long does a boiler service take?
Usually around an hour for a boiler in good condition, longer if it needs a deeper clean or a repair.
Is a boiler service the same as a gas safety check?
No. A gas safety check confirms appliances are safe. A service also cleans and checks the boiler so it keeps running well. They can be done at the same visit.