BoilerFaultCodesThe 6 most common faults
Your boiler has become too hot and has shut itself down as a safety precaution to prevent damage.
Ensure all radiator valves are open to allow water to flowWait for the boiler to cool down completelyTurn the selector switch to the reset position for five seconds and then release
Your boiler has stopped working because the water pressure in the system has dropped too low to operate safely.
Locate the external filling loop on the pipework beneath the boiler.Slowly open the tap or taps on the filling loop until you hear water entering the system.Monitor the pressure gauge and close the taps once the needle reaches between 1.0 and 1.5 bar.
Your boiler is struggling to move water around the system properly, causing it to overheat and shut down for safety.
Check that all radiator valves are fully openEnsure the boiler pressure is between 1.0 and 1.5 bar on the pressure gaugeBleed all radiators to remove trapped air that may be blocking water flow
Your boiler has tried to light several times but has been unable to establish a flame, often due to a lack of gas or a blocked condensation pipe.
Check that your gas supply is turned on and that other gas appliances (like a hob) are working.If it is freezing outside, check if the plastic condensate drain pipe leading outdoors has frozen and thaws it with warm water.Press the 'Reset' button for five seconds to see if the boiler restarts.
Your boiler's internal temperature sensor has stopped sending the correct information, preventing the system from heating your radiators safely.
Full guide for E20Your boiler has detected a problem with the sensor that monitors the temperature of the exhaust gases, causing the system to shut down for safety.
Full guide for E28on the Baxi Megaflo System 24 HE
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 Baxi 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