BoilerFaultCodesThe 6 most common faults
01
Lockout High DIY-safe
Your boiler has stopped working because it failed to light or stay lit, and it needs a manual restart to try again.
What to try first
Locate the reset button (marked 25 on your control panel).Press and hold the reset button for 2-3 seconds.Wait to see if the boiler ignites and the red light stops flashing.
02
Red indicator High Engineer
Your boiler has stopped working because it cannot light the gas burner or keep it burning.
Full guide for Red indicator03
Red lockout indicator High Engineer
Your boiler has failed to light the flame, so it has safely shut itself down to prevent gas from building up.
Full guide for Red lockout indicator04
Red indicator (22) High Engineer
Your boiler has stopped working because it cannot light the internal flame or detect that it is staying lit, so it has shut down for safety.
Full guide for Red indicator (22)05
Overheat detection High Engineer
Your boiler has shut itself down because it detected that it is running too hot, indicating a potential circulation or sensor problem.
Full guide for Overheat detection06
Red LED High Engineer
Your boiler has stopped working because it failed to start or got too hot, and it now needs to be manually restarted to begin operating again.
Full guide for Red LEDon the Chaffoteaux 80/100
Ignition electrodeGas valveFlame rectification probeFlame sensorPCBIonisation electrode
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 Chaffoteaux 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