What is a boiler service for?

A service is a planned check on a gas boiler while it is still working. The aim is to keep it safe, keep it efficient and spot wear before it turns into a breakdown. It is also one of the main ways faults that affect carbon monoxide safety, such as a damaged flue or poor combustion, get noticed before they cause harm.

Waiting until something goes wrong tends to mean waiting in the cold, often when engineers have the most call-outs. A routine visit lets you choose the timing, and a record of each service can help if you ever need to claim on a warranty.

What does the engineer do during a service?

The exact checks depend on the boiler, and engineers follow the manufacturer's instructions for each model. A service will often include:

opening the boiler and inspecting the burner, heat exchanger and seals
checking the flue from end to end, inside and outside the property
analysing the flue gases to see whether the boiler is burning correctly
checking the gas pressure or rate at the boiler
cleaning out the condensate trap, which catches the water a modern boiler produces
testing controls and safety devices
checking the system pressure, expansion vessel and visible pipework

Ask the engineer what their service covers when they contact you, so you know what you are agreeing to.

How often should it be done?

Once a year is the usual advice and what most manufacturers expect. There is no best month, but if you can book outside the coldest part of winter, appointments are often easier to arrange and any repair it turns up can be done before you depend on the heating.

Will skipping a service affect my warranty?

It might. Many boiler warranties depend on a yearly service carried out by someone on the Gas Safe Register, and some ask you to keep proof. Read your warranty terms, keep each service record somewhere you can find it, and make a note of the date the next one is due.

Do you have a hot water cylinder?

If your boiler heats a cylinder rather than giving hot water on demand, say so in your enquiry. Unvented cylinders, the sealed kind with no tank in the loft, have their own safety valves, and manufacturers usually recommend that these are checked regularly. It can be convenient to have this looked at on the same visit as the boiler.

Which warning signs should not wait for the yearly service?

Some signs point to a problem with how a gas appliance is burning and need attention straight away rather than at the next service:

a lazy yellow or orange flame where it would normally be blue
dark staining or soot on or around the boiler or a gas fire
a pilot light that keeps going out
more condensation than usual on windows in the room with the appliance

If you notice any of these, stop using the appliance and arrange for it to be checked. If anyone feels unwell, follow the carbon monoxide advice below.

I am a landlord. Is a service enough?

No. Landlords need a gas safety check every 12 months, and tenants must be given the record it produces. A service and a safety check are separate jobs, though many engineers can do both during one visit. Mention that you are a landlord in your enquiry and say which you need.

If your boiler is in a rented home and you are the tenant, servicing is normally arranged by the landlord. Ask them before booking anything yourself.

What should I tell the engineer?

the make and model of the boiler
when it was last serviced, if you know
whether it is still under warranty
whether there is a hot water cylinder
anything you have noticed lately, such as noises, slow hot water or pressure dropping

What happens after I enquire?

With your consent, we pass your enquiry to one Gas Safe registered engineer covering your corner of Hertfordshire. They contact you to agree a time and confirm the price directly. Sending an enquiry costs nothing and commits you to nothing.

We do not service boilers ourselves. We are an independent enquiry service, and the engineer may pay this site for each introduction.

What if I suspect carbon monoxide or smell gas?

Carbon monoxide has no colour, taste or smell, so a working alarm is the most reliable warning. Fit one in the room with the boiler if you do not have one. If it sounds, or you have headaches, nausea or dizziness that ease when you leave the house, open the windows, go outside and phone the National Gas Emergency Service on 0800 111 999. Use the same free number if you smell gas.

Who you will hear from

We pass your enquiry to one local heating engineer who covers your postcode. It is never sent to a list of companies.

We only pass enquiries to heating engineers whose registration we have checked on the Gas Safe Register. Ask to see their registration ID card when they arrive.

Herts Heating Repairs is an independent enquiry service, not a heating company. With your consent, we pass your enquiry to one local heating engineer who covers your area. The engineer may pay us a fee for each introduction.