BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water isn't moving through the system properly, which is causing it to overheat and shut down.
Check that your home's radiator valves are fully openCheck that the central heating pump is not stuck by gently tapping itBleed all radiators to remove trapped air that could be blocking water flow
Your boiler has stopped working because the water pressure in the central heating system has dropped too low to operate safely.
Locate the external filling loop, which is a silver braided hose usually found underneath the boiler or near the hot water cylinder.Slowly open the one or two valves on the filling loop until you hear water flowing.Watch the pressure gauge and close the valves tightly once the needle reaches between 1 and 1.5 bar.
Your boiler has likely overheated or a sensor has detected an incorrect temperature, causing the system to shut down for safety.
Wait for the boiler to cool down for 20 minutesEnsure all radiator valves are open to allow water to circulatePress the 'Reset' button on the front of the control panel
Your boiler has switched itself off because it has become too hot internally and needs to cool down for safety.
Wait for the boiler to cool down for at least 20 minutesEnsure all radiator valves are open to allow water to circulatePress the 'Reset' button on the control panel to restart the boiler
Your boiler is failing to light its burner after five attempts, which means it cannot provide heat or hot water and has gone into lockout for safety.
Check if other gas appliances, like a cooker, are working to ensure gas is reaching the propertyCheck if your prepayment gas meter has creditPress the 'Reset' button on the front of the boiler for five seconds
Your boiler has detected that its internal fan is not spinning correctly, which means it cannot safely vent exhaust gases and has shut down as a precaution.
Full guide for 4 red flasheson the Baxi Suprima 50
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