BoilerFaultCodesThe 6 most common faults
Your boiler is unable to light a flame, which means you will not have any heating or hot water at the moment.
Check if other gas appliances in your home, like a hob, are working to confirm your gas supply is active.If you have a prepayment meter, check that there is enough credit.Check if any external gas valves have been accidentally turned off.Press and hold the 'R' or reset button for at least five seconds to try and restart the boiler.
Your boiler has shut down because its internal temperature got too hot, acting as a safety precaution to prevent damage.
Check that your radiator valves are open and not turned to zero.Ensure there is enough water pressure in the system (typically 1.0 to 1.5 bar).Press and hold the Reset button for 5 seconds to see if the boiler restarts.
Your boiler has detected that there is not enough water in the system to operate safely and has shut down as a precaution.
Locate the filling loop (a silver flexible hose) usually found underneath the boiler.Slowly open the one or two taps/valves on the filling loop until you hear water moving.Watch the pressure gauge until it reaches between 1 and 1.5 bar, then close the valves tightly.Reset the boiler using the selector switch or reset button to clear the fault.
Your boiler has failed to light or maintain a flame, meaning your heating and hot water have stopped working for safety reasons.
Check that your gas supply is turned on and that other gas appliances are workingPress the red 'Flame Failure' reset button once to restart the ignition sequenceIf you have a prepay gas meter, ensure it has sufficient credit
Your boiler has become too hot and has switched itself off as a safety precaution.
Check that all radiator valves are open to allow water to flowEnsure the system pressure is between 1.0 and 1.5 bar on the gaugePress the white Reset button on the front of the control panel
Your boiler is using a combination of flashing or solid lights on the front panel to tell you it has detected a problem and may need a manual reset.
Check if the gas supply is active (e.g., check your gas meter or other gas appliances)Turn the selector switch to the 'Reset' position and hold for 5 secondsCheck that your central heating system pressure is between 1 and 1.5 bar on the gauge
on the Baxi Promax Combi
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