BoilerFaultCodesThe 6 most common faults
Your boiler's pump is running without enough water, likely because the system has lost pressure or the pump itself has become stuck.
Check the pressure gauge on the front of the boiler; if it is below 1.0 bar, top it up using the filling loopEnsure all radiator valves are open and any air has been bled from the systemRestart the boiler to see if the fault clears after the pressure is restored
Your boiler has lost its connection with your external wireless temperature controls, meaning it cannot receive the correct signals to turn on or off.
Check if the batteries in your room thermostat or programmer need replacingEnsure the wireless receiver plugged into the boiler is firmly in placeTurn the boiler power off and on again to attempt to re-establish the connection
Your boiler has switched itself off because it has detected that the internal water temperature has become dangerously high.
Check if your radiator valves are open to allow heat to escape the systemCheck your boiler pressure gauge and top up to 1.5 bar if it is too lowPress and hold the reset button for five seconds once the boiler has cooled down
Your boiler has stopped working because it cannot light the gas flame required to generate heat and hot water.
Check if other gas appliances in your home, like a hob, are working to confirm your gas supply is active.Ensure your prepaid gas meter has sufficient credit.If the weather is freezing, check if your external condensate pipe is frozen and thaw it with warm water.Press and hold the reset button for five seconds to see if the boiler restarts.
Your boiler has sensed that the water inside IT is getting too hot too quickly, causing it to shut down for safety.
Check that all radiator valves are fully open to allow water to circulate.Ensure there is no air trapped in the system by bleeding your radiators.Check that your boiler pressure is between 1 and 1.5 bar on the front gauge.
Your boiler has stopped working because it cannot light the gas or the flame has gone out unexpectedly.
Check if other gas appliances, like your hob, are working to ensure gas is reaching the propertyCheck that your prepay gas meter has creditPress and hold the Reset button for five seconds
on the Worcester Bosch 30i Junior
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 Worcester Bosch 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