Green light Low

Glow-worm Green light Fault Code

Also written as GREENLIGHT — same fault.

The Glow-worm Green light fault code means: your boiler is working correctly and is simply indicating that the internal burner is lit and ready to provide heating or hot water.. It appears on 2 Glow-worm models 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: Indicates that the pilot valve is held open, the thermoelectric valve and spark unit are de-energised, and the system is operating or ready.

What causes the Glow-worm Green light fault?

This indicator light means that your boiler has successfully sparked and established a flame to heat your water. It shows that the internal gas valve is open and the system is functioning exactly as it should be. There is no fault present, and the light is simply confirming that the burner is currently active.

DIY fix possible

This fault may be fixable without an engineer. Check your manual first.

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Glow-worm models that show the Green light fault code

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

Source

Glow-worm Green light 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 27 April 2026