BoilerFaultCodesThe 6 most common faults
Your boiler has shut down because the internal water temperature has become too hot, causing it to lock out for safety.
Check that all radiator valves are fully openEnsure the boiler pressure is between 1.0 and 1.5 barTry resetting the boiler once the unit has cooled down
Your boiler has failed to ignite after several attempts, meaning the system cannot provide heating or hot water until it is reset.
Check that your gas supply is turned on (check other gas appliances like your hob).Press and hold the 'Reset' button for five seconds.If the boiler has been off for a long time, repeat the reset process up to three times to clear air from the pipes.
Your boiler has failed to ignite after several attempts, meaning you will not have any heating or hot water until the system is reset or repaired.
Check that your gas emergency control valve is in the 'on' position and you have credit on your meter.Press the 'Reset' button on the boiler control panel for two seconds.Ensure the condensate pipe (the plastic pipe leading outside) is not frozen if it is currently very cold weather.
Your boiler has become too hot and has shut down as a safety precaution to prevent damage.
Check that all radiator valves are fully openEnsure the boiler pressure is between 1.0 and 1.5 barWait for the unit to cool down below 50°C before attempting to reset
Your boiler is struggling to detect the flame it has lit, causing the system to shut down for safety.
Check that your gas emergency control valve is open and you have credit on your gas meterTest if other gas appliances in the home, such as a hob, are working correctlyPress the reset button once to see if the boiler restarts
Your boiler has detected an internal communication error between the main control board and its display or ignition system, preventing it from starting up.
Full guide for H Eon the Evo HE C22/30
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 Evo 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