LED 1 Lit, LED 2 Off High

Glow-worm LED 1 Lit, LED 2 Off Fault Code

Also written as LED1LITLED2OFF — same fault.

The Glow-worm LED 1 Lit, LED 2 Off fault code means: your boiler has encountered a serious internal error and has safely shut itself down to prevent damage, meaning you currently have no heating or hot water.. 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: Non - Volatile Lockout
Typical repair cost £150-350 (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 LED 1 Lit, LED 2 Off fault code

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

Source

Glow-worm LED 1 Lit, LED 2 Off 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