BoilerFaultCodesGlow-worm F63 Fault Code
The Glow-worm F63 fault code means: your boiler's internal computer brain has developed a memory error and can no longer process its instructions correctly.. It appears on 8 Glow-worm models in our database.
Technical description: Main PCB memory fault
What causes the Glow-worm F63 fault?
This fault occurs when the boiler's main control board suffers a hardware failure, specifically within its internal memory chip. It is usually caused by electrical wear and tear over time or a sudden power surge that corrupts the data the boiler needs to operate safely. Effectively, the board can no longer read its own internal instructions and must be replaced.
This fault is slightly more common during the winter months when boilers are under higher operational stress and stormy weather increases the risk of electrical surges.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Glow-worm models that show the F63 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm F63 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