High Lockout
Reset Neon (Flashing) on Potterton Performa 24

Your boiler has tried to fire up but could not light the flame, causing it to shut down for safety.

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

Indicates that the burner has failed to light. To reset the boiler turn the selector switch to the reset position.

What causes this fault?

This fault occurs when the boiler's internal sensor fails to detect a flame after several attempts to start. The most common reasons are a lack of gas reaching the burner, a faulty spark that cannot ignite the gas, or a sensor that is too dirty to see the flame that has been lit.

This issue is more frequent during extreme cold spells, as external gas meters or pipes can occasionally freeze and restrict the gas flow required for ignition.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer
Search the official register →

Related guides you might find useful