High
lockout light on Potterton Combi 80

Your boiler has stopped working because it cannot light its internal flame, which could be due to a gas supply issue or a safety cutout.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Loss of gas supply, flame failure, or over-heating of the central heating water will cause the appliance to shut down or Lockout. This will be indicated by the lockout light being illuminated.

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

Boiler keeps cutting out

Lockout fault with a reset-needed pattern.

Read →

Boiler won't turn on — 9-step checklist

Work through these before the call-out.

Read →

Pilot light keeps going out

Older boilers — thermocouple, draught, gas supply.

Read →