Seeing fault codes like F1, F9, F22, or F25 on your Glow-Worm boiler can be worrying. By grasping what these specific codes mean and knowing the right steps to follow, you can manage minor troubleshooting or decide when it is necessary to bring in a professional heating engineer. In this post, we break down these common fault codes and advise on the steps you should take.
F1 – Ignition Failure:
If your unit has attempted to ignite five times unsuccessfully and triggered a ‘lock out,’ try a system reset and request heat. Should the problem continue, examine the condensate waste pipe to confirm it isn’t blocked or frozen at the drainpipe connection point. If you find you are resetting the boiler often or the issues remain, please reach out to us for expert help, as this may point to deeper mechanical faults or the need for component replacement.
F4 – Repeated Ignition Failure:
Like the F1 code, if your boiler has failed to light five times and locked out, first ensure your gas supply is turned on at the meter and that you have sufficient credit if you use a pre-payment meter. Test your gas hob to verify a consistent supply. Attempt a reset and call for heat. If the fault does not clear, contact us for professional support.
F9 – Pressure Issues:
When your boiler identifies a pressure-related fault, look at the pressure gauge and use your filling loop to top it up if the reading is low. Even if the pressure appears normal, a brief top-up can sometimes help, though be careful not to exceed 1.5bar or push the needle into the red zone. Occasionally, debris can obstruct the pressure sensor, which may require cleaning or a full replacement. This could also be a sign that your heating system requires a magnetic filter or perhaps a power flush. See our blog post on Repressurising your boiler in Wokingham, Berkshire.
F22 – Pressure Check and Reset:
Inspect the pressure gauge and perform a top-up if the levels are low, then attempt a reset. If the fault code returns or you are frequently dealing with an F22 error, contact our team for a detailed inspection and fix. See our blog post on Repressurising your boiler in Wokingham, Berkshire.
F25 – Heat Dispersion Challenge:
If the boiler is having trouble circulating heat, check the current pressure and top up if it’s required. Perform a reset and try setting your flow temperature to 65 degrees (or lower for combi boilers). Reach out to us for further assessment, as this error is frequently caused by restricted flow through the heat exchanger, often due to pump issues or blockages within the heat exchanger or the wider central heating system.
You can contact The Boilersmith if you’re in Wokingham Borough—including Woodley, Twyford, Wokingham, Winnersh, Earley, Lower Earley, Reading, or surrounding areas in Berkshire—for an annual boiler service, urgent repairs, heating maintenance, or a quote for a new installation. Our Gas Safe-registered engineers are highly experienced with all leading brands, including Glowworm, Vaillant, Worcester, Viessmann, Ideal, Potterton, Baxi, and Main Gas boilers.