BoilerFaultCodesGlow-worm F29 Fault Code
The Glow-worm F29 fault code means: your boiler has lit successfully but then lost its flame while it was running, causing the system to shut down for safety.. It appears on 8 Glow-worm models in our database.
Technical description: Loss of flame during operation fault
What causes the Glow-worm F29 fault?
This fault occurs when the boiler successfully starts but cannot maintain a steady flame, causing it to shut down for safety. The most common reasons are a temporary interruption in the gas supply, a dirty flame sensor that can no longer 'see' the fire, or a buildup of debris in the burner area.
This fault is more common in winter, as a frozen external condensate pipe can cause water to back up into the boiler and extinguish the flame.
DIY fix possible
Check that your gas emergency control valve is fully open and you have credit on your meter.Verify if other gas appliances in your home, such as a hob, are working correctly.Gently press the reset button (indicated by a flame with a line through it) to see if the system restarts.
Find a Gas Safe engineer
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A cover plan would handle faults like F29: no call-out fees, no surprise bills.
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Glow-worm models that show the F29 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm F29 fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.
- Glow-worm Betacom2 28 manual (PDF)
- Glow-worm Easicom 28 manual (PDF)
- Glow-worm Ultracom 2 35cxi manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026