G20 Low

Glow-worm G20 Fault Code

The Glow-worm G20 fault code means: your boiler is displaying a code indicating it is set up to run on natural gas, but it does not represent a physical fault with the machine itself.. It appears on 1 Glow-worm model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Natural Gas (G20)

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 G20 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Glow-worm G20 fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026