BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water pressure inside the system has dropped too low.
Locate the filling loop, which is usually a flexible silver hose with one or two valves underneath the boiler.Open the valve(s) slowly to allow cold mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close the valve(s) tightly and check that the fault code has cleared.
Your boiler's flame has gone out because air has entered the gas pipes or the gas supply is not steady enough to keep it running.
Check if other gas appliances, like a cooker, are working properly to confirm gas supply.Press and hold the 'R' or Reset button for at least five seconds.If the fault persists after three reset attempts, you must call a Gas Safe engineer.
Your boiler is struggling to light because there is either a blockage in the gas supply or air trapped in the pipes, often caused by a recent gas interruption or frozen pipes.
Check that your gas meter has credit and the isolation valve is openTurn on a separate gas appliance, like a hob, to help purge air from the systemPress and hold the Reset button for five secondsCheck if the white condensate pipe outside is frozen; if so, thaw it with warm water
Your boiler has detected that water isn't moving through the system properly, which is causing it to shut down to prevent overheating.
Check that the central heating valves under the boiler are fully open.Ensure all radiator valves (TRVs) are turned to the highest setting.Check the system pressure gauge and top up to 1.5 bar if it is too low.Gently bleed your radiators to remove any trapped air.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Locate the filling loop (braided silver hose) underneath or near the boiler.Open the one or two taps on the loop slowly until you hear water entering the system.Close the taps once the pressure gauge on the boiler reaches between 1.0 and 1.5 bar.
Your boiler has detected that water is not moving around the system correctly, causing it to overheat and shut down for safety.
Check that your radiator valves are openEnsure the system pressure is between 1 and 1.5 barGently bleed your radiators to remove trapped air
on the Baxi 124 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