BoilerFaultCodesThe 6 most common faults
Your boiler has sensed it is getting too hot and has shut itself down as a safety precaution.
Check that your radiator valves are openEnsure there is enough water pressure in the systemWait for the boiler to cool down and press the reset button
Your boiler has detected that the water pressure in the system is too low to operate safely.
Locate the filling loop (usually a silver flexible hose) underneath or near the boiler.Slowly open the valve(s) to allow water into the system while watching the pressure gauge.Close the valves once the needle reaches between 1.0 and 1.5 bar, then reset the boiler.
Your boiler is struggling to move hot water around your heating system, causing it to overheat and shut down for safety.
Check that your radiator valves and any external isolation valves are fully openBleed all radiators to remove trapped air that might be blocking water flowGently restart the boiler using the reset button
Your boiler has tried to light several times but cannot establish a steady gas supply or sense a flame, causing it to shut down for safety.
Check if your gas meter has credit (if on a prepay meter).Ensure your external gas emergency control valve is in the 'on' position.Attempt to reset the boiler using the reset button or dial once the gas supply is confirmed.
Your boiler has detected that water is not moving through the system quickly enough before the burner ignites, often due to a blockage or a pump issue.
Check that your central heating valves and radiator valves are fully openEnsure the system water pressure is topped up to between 1 and 1.5 barGently bleed your radiators to remove any trapped air pockets
Your boiler has become too hot and has shut down as a safety precaution to prevent damage.
Check that all radiator valves are fully openBleed your radiators to remove trapped air using a radiator keyWait for the boiler to cool down and press the reset button
on the Baxi Suprima 100
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