Summer mode LED Low

Glow-worm Summer mode LED Fault Code

Also written as SUMMERMODELED — same fault.

The Glow-worm Summer mode LED fault code means: your boiler is failing to switch into summer mode due to an internal electronic circuit board failure.. 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: Failure to illuminate when button pressed - Change P.C.B.

What causes the Glow-worm Summer mode LED fault?

This fault occurs when the internal electronic components responsible for registering button presses on the control panel have degraded or failed. The most common reason is a physical breakdown of the circuitry on the printed circuit board, which prevents the boiler from acknowledging the command to switch modes.

This issue is often discovered in late spring or early summer when homeowners attempt to switch off their central heating for the warmer months.

Typical repair cost £280-450 (including labour)

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 Summer mode LED fault code

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

Source

Glow-worm Summer mode LED 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