A gas boiler should be serviced once a year. That is the advice from Gas Safe Register and most boiler manufacturers, and many manufacturers make an annual service a condition of the warranty.
Here is what a service involves, why it matters and the signs that a boiler needs looking at before its next one is due.
Why once a year?
A boiler burns gas every time the heating or hot water comes on. Over a year, parts wear, seals age and deposits build up. A yearly service catches small problems before they turn into breakdowns, usually in the middle of winter.
It is also about safety. A badly burning boiler can produce carbon monoxide, which you cannot see, smell or taste. A service checks that the boiler is burning gas properly and that the flue is taking the fumes safely outside.
Many people book their service in late summer or early autumn, before the heating goes on for winter. That way any problem is found while you can still manage without the heating for a day or two.
What happens during a boiler service
A proper service is more than a quick look and a signature. The details vary by boiler, but a service typically covers:
- A visual check of the boiler, its casing and seals
- Checking the flue and the ventilation around the boiler
- Checking gas pressures and how the burner is working
- Testing the safety devices and controls
- Checking efficiency and flagging any faults
- A clear explanation of what was found and anything that needs doing
Does a service affect my warranty?
Very often, yes. Many boiler manufacturers require the boiler to be serviced every year by a Gas Safe registered engineer for the warranty to stay valid. If a service is missed, a later warranty claim can be refused.
The exact terms vary between manufacturers, so check your warranty paperwork and keep a record of every service.
If you have just moved into a home, ask the seller or landlord for the boiler service history. If there is none, book a service so you know where you stand.
Signs your boiler needs looking at now
Do not wait for the annual service if you notice any of these:
- The boiler keeps losing pressure or needs topping up
- Radiators are cold in places or take a long time to warm up
- Unusual noises such as banging, gurgling or whistling
- Black marks or staining on or around the boiler
- A carbon monoxide alarm going off
- The boiler keeps locking out or showing fault codes
- On appliances where you can see the flame, a yellow or orange flame instead of a crisp blue one
If you smell gas or your CO alarm sounds
If you smell gas, or your carbon monoxide alarm goes off, treat it as an emergency. Turn off the gas at the meter if it is safe to do so, open doors and windows, do not use electrical switches, get everyone outside and call the National Gas Emergency Service on 0800 111 999. Do not use the appliance again until a Gas Safe registered engineer has checked it.
It is worth having an audible carbon monoxide alarm in any room with a gas appliance. They are cheap and easy to fit.
What about landlords?
If you let a property, the rules are stricter. Landlords must have a gas safety check carried out every 12 months on the gas appliances and flues they provide, by a Gas Safe registered engineer.
A gas safety check is not the same as a full boiler service, although both can often be done on the same visit. Our guide to the landlord gas safety certificate covers the rules in more detail.
Need a gas engineer?
G Freeman Gas Heating and Plumbing carries out annual boiler servicing and landlord gas safety checks across Gloucester, Cheltenham and the surrounding area. Gary checks the flue, ventilation and gas pressures properly rather than just wiping the boiler down and signing a form. Quotes are free and there is no call-out charge.
Read more about boiler servicing & landlord gas safety and boiler breakdowns & emergency repairs, or see the areas covered in Gloucester and Cheltenham.