Red light (flashing) High

Glow-worm Red light (flashing) Fault Code

Also written as REDLIGHTFLASHING — same fault.

The Glow-worm Red light (flashing) fault code means: your boiler has encountered an internal error and needs a simple restart to try and clear the fault.. It appears on 1 Glow-worm model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: General fault; requires momentary interruption of the electrical supply to reset.

What causes the Glow-worm Red light (flashing) fault?

This fault occurs when the boiler's internal electronics detect a communication error or a safety interruption that prevents the system from starting. The most common reason is a temporary glitch in the control board or a sensor that has tripped due to minor overheating or a failed ignition attempt. It acts as a safety barrier to ensure the boiler does not operate until a qualified person or a manual reset has cleared the issue.

Typical repair cost £90-280 (including labour)

DIY fix possible

Locate the electrical spur switch or plug for the boilerTurn the power off for approximately 30 secondsTurn the power back on to see if the flashing light stops and the boiler restarts

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Glow-worm models that show the Red light (flashing) fault code

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

Source

Glow-worm Red light (flashing) 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