Lockout (rapid flashing) High

Potterton Lockout (rapid flashing) Fault Code

Also written as LOCKOUTRAPIDFLASHING — same fault.

The Potterton Lockout (rapid flashing) fault code means: your boiler has failed to start after several attempts to ignite the burner, so it has safely shut itself down to prevent wasting gas.. 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.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like Lockout (rapid flashing): no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Potterton models that show the Lockout (rapid flashing) fault code

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

Source

Potterton Lockout (rapid flashing) 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