LED 1 Slow Flashing (2Hz) High

Glow-worm LED 1 Slow Flashing (2Hz) Fault Code

Also written as LED1SLOWFLASHING2HZ — same fault.

The Glow-worm LED 1 Slow Flashing (2Hz) fault code means: your boiler has entered a safety lockout mode because it failed to light or stay on properly after multiple attempts.. It appears on 4 Glow-worm models 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

What causes the Glow-worm LED 1 Slow Flashing (2Hz) fault?

This fault occurs when the boiler's control system detects that a flame has not been successfully established or maintained after several ignition cycles. The most common reasons include a worn-out spark probe that can no longer ignite the gas, or a faulty gas valve preventing fuel from reaching the burner.

Typical repair cost £100-350 (including labour)

DIY fix possible

Locate the reset button or selector switch on the front control panel.Turn the selector switch to the 'Reset' position or press the reset button for five seconds.Check if your gas prepay meter has credit and that other gas appliances in your home are working.

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Glow-worm models that show the LED 1 Slow Flashing (2Hz) fault code

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

Source

Glow-worm LED 1 Slow Flashing (2Hz) 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