BoilerFaultCodesGlow-worm Red flashing light (Gas) Fault Code
Also written as REDFLASHINGLIGHTGAS — same fault.
The Glow-worm Red flashing light (Gas) fault code means: your boiler has stopped working because it cannot get a steady supply of gas to stay lit.. It appears on 1 Glow-worm model in our database.
Technical description: Gas supply is interrupted; boiler switches over to safety mode.
What causes the Glow-worm Red flashing light (Gas) fault?
This fault occurs when the boiler tries to light the flame but fails to detect one, causing the system to shut down for safety. The most common reasons are a temporary interruption in your gas supply, worn-out ignition parts that can no longer create a spark, or a faulty internal valve that isn't opening properly.
This issue is more frequent during extreme cold spells, as external gas meters or regulators can occasionally freeze or become sluggish, restricting fuel flow to the appliance.
DIY fix possible
Check if other gas appliances, like a cooker, are working to confirm your gas supply is active.If you have a prepayment meter, check that you have enough credit.Locate your gas meter and ensure the main handle is in the 'on' position.Reset the boiler by turning the main selector dial to 'Reset' for five seconds, then back to your preferred setting.
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Gas Safe Register →Glow-worm models that show the Red flashing light (Gas) fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm Red flashing light (Gas) 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