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You may have come across F1, F9, F22 and F25 fault codes with your Glow-Worm boiler. Understanding these codes and knowing what steps to take can help you troubleshoot or sometimes fix simple common issues or know when to call in a heating engineer. In this article, we will explain what these fault codes mean and provide guidance on what actions to take.

F1 – Your boiler has failed to light 5 times and gone to ‘lock out’. Try resetting the boiler and calling for heat. If this fails to work check your condensate waste pipe isn’t frozen or blocked where the condensate pipe connects to a drainpipe. If you regularly have to reset your boiler or can’t get it to operate, please get in contact so we can fix it for you as it may be something more complicated or a part/parts need replacing.
F4 – Your boiler has failed to light 5 times and gone to ‘lock out’. Check the Gas hasn’t been turned off at your gas meter or that you have sufficient credit if it’s a prepaid meter. You can check your gas hob if you have one. Try resetting the boiler and calling for heat. If you regularly have to reset your boiler or can’t get it to operate, please get in contact so we can fix it for you.
F9 – The boiler is sensing a pressure issue. Check your pressure gauge and top up with the filling loop controls if low. If it isn’t, try giving it a quick top up anyway but best to avoid going over 1.5bar/into the red. Sometimes debris has got caught in the pressure sensor which is best replaced which we can do for you. This can also be a sign your central heating system would benefit from a magnetic filter and possibly a power flush.
F22 – Check pressure gauge, top up if necessary. Try a reset. If this fails to work or you are repeatedly getting an F22 fault code/resetting contact us to investigate/fix.
F25 – The boiler is struggling to disperse the heat being created. Check the pressure and top up if necessary, try a reset. Turn down the flow target temperature to 65 degrees (you can go lower if a combi boiler). Call us to investigate as this is often caused by blockages in the heat exchanger or central heating system.

If you live in the Woodley, Twyford, Wokingham, Winnersh, Earley, Lower Earley, Reading, or surrounding areas in Berkshire, please don’t hesitate to contact The Boilersmith to arrange an annual boiler service, boiler repair, central heating repair or a quotation for a replacement boiler. Our Gas Safe Registered heating engineers are highly experienced with all major manufacturers including Worcester, Vaillant, Viessmann, Ideal, Potterton, Baxi and Main Gas boilers.