Glow-worm F11 Fault Code Guide for Homeowners: Meaning, Symptoms, Actions, Prevention
The Glow-worm F11 fault code means there is a communication problem between the User Interface PCB and the Main PCB. The main symptoms include the boiler failing to start, an error code display, and intermittent operation. This fault has safety implications, as unresolved issues can lead to further damage. The cause is a fault or damage to wiring or electrical components of the boiler. Preventative measures are regular inspection and maintenance, prompt repair of leaks, and using high-quality parts when servicing.
Always use a Gas Safe engineer for any repairs.
Meaning of the Glow-worm F11 Fault
The Glow-worm F11 fault means there is a communication problem between two circuit boards on the boiler. These are the User Interface PCB, with the user controls and display, and the Main PCB which controls the boiler. This issue occurs mostly due to loose or damaged wiring, faulty connectors, or a defective PCB. The F11 fault will cause the boiler to enter a system lockout to protect it from further damage.
What causes the communication problem in the F11 fault?
Loose or damaged wiring between the User Interface PCB and the Main PCB causes the communication problem. Faulty thermistors or defective PCBs also contribute to this issue.
How does the boiler detect the F11 fault?
The boiler detects the F11 fault when it does not recognise the signals going between the two PCBs. When the PCBs are unable to talk to one another, it triggers the error code display and system lockout.
Can a user fix the F11 fault themselves?
No, a user cannot fix the F11 fault themselves. The F11 Glow-worm fault code is an electrical problem that needs a qualified Gas Safe engineer to diagnose and fix it.
Is the F11 fault common in Glow-worm boilers?
Yes, the F11 fault is quite common in Glow-worm boilers. It’s more common in older models where wiring and PCB components may have degraded over time.
Symptoms of the Glow-worm F11 Fault
The main symptoms of the Glow-worm F11 fault code are the boiler displaying F11 and failing to operate or provide hot water. Resetting the boiler might fix it if the connection issue is intermittent. But, the error will return and cause a lockout.
How To Recognise The F11 Fault on Different Types of Glow-worm Boiler
Glow-worm Combi Boilers: The boiler will not run, and the display will keep showing the F11 code even with repeated reset attempts.
Glow-worm System Boilers: For Glow-worm System boilers, the symptoms are similar. The digital display will show the F11 fault code. The boiler will lockout, preventing it from providing hot water or central heating. You may notice that the boiler tries to start but then stops, displaying the error code.
Older Non-Digital Boilers: In older, non-digital Glow-worm boilers, recognising the F11 fault is more challenging. These boilers lack a digital display, so symptoms include the boiler failing to start, no hot water, and no central heating. An engineer will need to diagnose the fault by checking the wiring and PCB components.
What to Do When Your Glow-Worm Boiler Shows the F11 Fault
When your Glow-worm boiler displays the F11 fault code, turn off the boiler and call out a Gas Safe registered boiler engineer. This helps to prevent further damage to the boiler. Check your boiler’s instruction manual for specific instructions on how to turn off the power safely.
Safety Disclaimer
Always follow the instructions in your boiler’s manual. Do not attempt to repair or diagnose issues beyond basic checks. Use a qualified Gas Safe engineer for any further inspection or repair work. Handling gas appliances without proper training can be dangerous and may be illegal.
How to Turn Off My Glow-worm Boiler Safely?
First check that you cannot smell gas. If you suspect a gas leak, evacuate the area immediately and do not operate any electrical device or switches. Open windows for ventilation and contact your gas supplier’s emergency line immediately.
If there is no gas leak, turn off the boiler using the main power switch or the dedicated isolation switch. Refer to your boiler’s manual for exact instructions.
Where Can I Find a Qualified Gas Safe Engineer?
You can call us or use our contact page and we’ll put you in touch with a local qualified Gas Safe engineer. You can also search on the Gas Safe Register website.
How to Check for Gas or Water Leaks Around My Boiler?
Inspect the area around your boiler for unusual smells, particularly the smell of gas, and look for water pooling or dripping. If you detect a gas leak, evacuate the area immediately and contact emergency services. If you find a water leak, shut off the water supply and contact a Gas Safe engineer.
Should I Attempt to Reset the Boiler Myself?
No, do not attempt to reset the boiler yourself after detecting the F11 fault. Resetting without addressing the underlying issue can cause more damage. Let a Gas Safe engineer handle the reset after performing necessary repairs.
Preventing Future F11 Faults
Annual boiler maintenance is the most effective way to prevent future F11 faults. Regular servicing by a qualified Gas Safe engineer ensures that all components, including the User Interface PCB and Main PCB, are in good working order. During a service, the engineer checks for any signs of wear or damage to the wiring and connections. A boiler service contract provides peace of mind, ensuring that maintenance is performed consistently and any emerging issues are addressed promptly. Keeping your boiler clean and free of dust or debris also helps maintain optimal function.
Disclaimer
Only do the safe basic operation and maintenance as described in the user manual. A Gas Safe registered engineer should do all other work. Handling gas appliances without proper training is dangerous and the consequences can be deadly. Always ensure safety by relying on professional expertise for repairs and diagnostics.