BoilerFaultCodesThe 6 most common faults
Your boiler has detected that water is not circulating properly, most likely because the system pressure has dropped too low to operate safely.
Check the pressure gauge on the front of the boiler; if it is below 1 bar, your system pressure is too low.Locate the filling loop (a silver braided hose or a small key valve) underneath the boiler.Open the filling valve slowly until the needle on the gauge reaches between 1 and 1.5 bar, then close the valve tightly.
Your boiler has stopped working because there is either not enough water inside the system or an internal part that moves the water around has stopped running.
Check the pressure gauge on the front of the boiler; if it reads below 1 bar, your system needs to be re-pressurisedLocate your external filling loop (a flexible metal or braided hose connecting two pipes)Open the valves on the filling loop to allow cold mains water in until the needle reaches 1.5 bar, then ensure the valves are tightly closed
Your boiler has stopped working because it cannot light the internal flame or keep it burning.
Full guide for 20Your boiler has detected that it is overheating and has automatically switched itself off to prevent damage.
Full guide for 21Your boiler has stopped working because it is unable to accurately measure the temperature of the water being sent to your radiators.
Full guide for 25Your boiler is failing to light the internal flame, which means it cannot produce any heat or hot water and has shut down as a safety precaution.
Full guide for Neon 4on the Baxi System 35/60 / 60/100
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