Boiler not working? Check these first.
Simple checks you can do safely yourself before calling an engineer. If they don’t fix it, call us: we repair gas boilers of all makes across Blackpool, Lytham St Annes, Fleetwood, Cleveleys, Poulton-le-Fylde and Kirkham and nearby.
Stop and get help if
- You smell gas. Don’t switch anything on or off. Open the windows, leave the property and call the National Gas Emergency Service free on 0800 111 999.
- Your carbon monoxide alarm goes off, or people at home get headaches, dizziness or sickness that ease when they go outside. Turn the boiler off, open the windows, get everyone outside, call 0800 111 999 and get medical advice.
- The flame is yellow or orange instead of a crisp blue, or there’s soot or brown staining on or around the boiler.
- The fix means taking the boiler’s cover off. Only a Gas Safe registered engineer should work inside a boiler.
Checks you can do
Check the power, thermostat and timer
Check the boiler’s display is on and the switch next to it is on. Turn the room thermostat up a few degrees and check the timer or programmer is set to heating on. After a power cut, the clock may need setting again.
Check the pressure
Most combi and system boilers need between 1 and 1.5 bar on the gauge when the heating is cold. If it’s below 1, top it up using the filling loop, following your boiler’s manual, then reset the boiler. If the pressure keeps dropping, there’s a leak somewhere, so call us. See your make of boiler below for how yours tops up.
Thaw a frozen condensate pipe
In freezing weather, the plastic pipe that runs from the boiler to a drain outside can freeze, and the boiler stops with a fault code. Pour warm water (not boiling) over the outside part of the pipe, or hold a hot water bottle against it, then reset the boiler. Don’t climb a ladder to reach it.
Bleed your radiators
If a radiator is cold at the top and warm at the bottom, it has air in it. With the heating off and the radiators cool, open the bleed valve with a radiator key until water comes out, then close it. Check the boiler pressure afterwards, because bleeding lowers it.
Reset the boiler
Most boilers have a reset button. Pressing it once is fine. If the boiler keeps locking out, stop resetting it and call us.
Topping up the pressure on your make of boiler
Each boiler maker does it slightly differently. Choose yours for a short summary and links to the maker’s own guide and fault codes.
Worcester Bosch
Worcester boilers are topped up in one of three ways: an external filling hose with two valves; a filling key, usually kept on a flap under the boiler, that pushes into a port on the front right-hand side; or, on newer models, a blue lever under the boiler that you pull down until the gauge reads just over 1 bar. Worcester has a video showing how to tell which one you have.
Vaillant
Vaillant’s advice is to top up through the filling loop as your boiler’s instructions say, and to close the loop and call an engineer if the pressure doesn’t rise. If the display shows F.22 (low water pressure), Vaillant’s fault code list advises calling an engineer rather than fixing it yourself.
Ideal
Ideal says the pressure should be 1 to 1.5 bar when the system is cold. On combi boilers the filling loop is under the boiler, usually a silver flexible hose or a ridged pipe joining two pipes in a horseshoe shape. Open the valves slowly, because the pressure can rise quickly. On boilers made before 2016 the gauge may be on the pipework under the boiler rather than on the front. System and heat-only boilers may have the filling loop somewhere else, such as near the hot water cylinder.
Baxi
Newer Baxi boilers have a digital pressure gauge on the front and a green Easyfill filling loop underneath; error codes A.02.06 or H.02.07 mean the pressure is too low. Baxi recommends 1 to 2 bar and asks you to watch its video to the end before topping up. Baxi also says codes E28, E53, E119, E128 or E133 can mean a frozen condensate pipe (see the thawing tip above).
Viessmann
Viessmann says most boilers should sit at 1 to 1.5 bar, in the green section of the gauge. The filling loop is either external (removed once you’ve finished) or built in, and some older combis use a filling key instead. If the pressure goes above 2.75 bar, bleed a radiator to bring it down.
Glow-worm
Glow-worm boilers usually have a silver flexible filling loop with two small valves underneath. With the heating off and the pipes cool, turn both valves a quarter turn anticlockwise, stop at 1 to 1.5 bar, then close them fully. The boiler then runs a 5-minute purge, when the heating and hot water won’t work. Some older combis use a filling key instead. F.22 means low water pressure; if the gauge reads above 1 bar and the boiler still shows F.22, Glow-worm says it needs an engineer.
Another make
Find your boiler’s make and model on the front or under a flap, then look up its user manual on the maker’s website. Most makers have a pressure guide or video there. If you’re not sure, call us.
Summaries of each maker’s own guidance, checked in October 2026. Always follow your boiler’s manual. If what you see doesn’t match, stop and call us.
Keep it running well
- Have it serviced every year. Most makers need this for the warranty.
- Run the heating for 15 minutes once a month in summer, so the pump and valves don’t seize.
- Keep the space around the boiler and its flue clear.
- Fit a carbon monoxide alarm in every room with a gas appliance.
Still not working?
Call us or send the form with what the boiler is doing and any fault code on the display. We repair gas boilers of all makes.
If it’s old and keeps breaking down, it may be time for a new boiler.
Send an enquiry
Tell us what you need and we'll get back to you. You can also call 07498 614173 or email enquiries@networknw.com.
Smell gas? Don't use this form. Call the National Gas Emergency Service free on 0800 111 999, 24 hours a day.