Red light flashing (Lockout) High

Potterton Red light flashing (Lockout) Fault Code

Also written as REDLIGHTFLASHINGLOCKOUT — same fault.

The Potterton Red light flashing (Lockout) fault code means: your boiler has failed to start up or stay lit and has now shut itself down for safety, meaning you currently have no heating or hot water.. It appears on 2 Potterton 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: Ignition failure after three attempts
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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Potterton models that show the Red light flashing (Lockout) fault code

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

Source

Potterton Red light flashing (Lockout) fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026