BoilerFaultCodesThe 6 most common faults
01
Boiler at lock out High DIY-safe
Your boiler has stopped working as a safety precaution and needs to be manually restarted to see if it can clear the internal error.
What to try first
Locate the reset button on the front control panelPress and hold the reset button for 3-5 secondsWait a few minutes to see if the burner ignites; if it locks out again immediately, stop and call a professional
02
Burner lock out neon High Engineer
Your boiler has failed to light the flame after several attempts and has shut itself down for safety.
Full guide for Burner lock out neon03
Limit stat tripped High Engineer
Your boiler has automatically shut down because it overheated, likely due to a flow issue or a sensor malfunction.
Full guide for Limit stat tripped04
Locks Out In Morning Only High Engineer
Your boiler is struggling to ignite when it first wakes up in the morning, likely because it is having trouble breathing or moving water correctly.
Full guide for Locks Out In Morning Only05
Lockout High Engineer
Your boiler has stopped itself from running due to a fuel or ignition issue, and it requires a manual reset to attempt to start again.
Full guide for Lockout06
Overheat High Engineer
Your boiler has detected that it is running too hot and has automatically switched itself off to prevent potential damage.
Full guide for Overheaton the Potterton Statesman
Ignition electrodeFlame rectification probeControl PCBPhotocellIgnition transformerOil pump
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Potterton shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue