Lockout (Rapid Flashing Red) High

Potterton Lockout (Rapid Flashing Red) Fault Code

Also written as LOCKOUTRAPIDFLASHINGRED — same fault.

The Potterton Lockout (Rapid Flashing Red) fault code means: your boiler has failed to start after several attempts and has switched itself off for safety, usually because it cannot detect a flame or is struggling to get fuel.. 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: The boiler will attempt to light, if the boiler does not light within 3 attempts (due to air in the system) the boiler controls will go to 'Lockout' and the upper Red LED on the control panel will go to a rapid flashing mode.
Typical repair cost £120-250 (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 Lockout (Rapid Flashing Red) fault code

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

Source

Potterton Lockout (Rapid Flashing Red) 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 7 July 2026