Home/Boiler Fault Codes/Glow-worm F28
GLOW-WORM FAULT CODE
Glow-worm F28
An ignition fault. In cold weather, F1, F4, F28 and F29 on Glow-worm boilers are frequently linked to a frozen external condensate pipe blocking normal drainage.
WHAT F28 TYPICALLY INDICATES
An ignition fault. In cold weather, F1, F4, F28 and F29 on Glow-worm boilers are frequently linked to a frozen external condensate pipe blocking normal drainage.
WHAT TO DO
If the external condensate pipe is visible and looks frozen, gently warming it with a warm damp cloth is a documented homeowner step — never boiling water, never opening the casing. If that doesn't clear it, This is not a DIY fix — it requires a Gas Safe registered engineer to diagnose and repair safely.
A NOTE ON GAS SAFE REGISTRATION
Any work on the gas side of a boiler in the UK legally requires a Gas Safe registered engineer, it isn't optional. Our engineers are fully Gas Safe registered, and you're always welcome to ask to see ID on the day. This page is general information about what a fault code typically indicates; it is not a substitute for an engineer diagnosing your specific boiler.
Seeing Glow-worm F28 on your boiler?
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