BoilerFaultCodesThe 6 most common faults
Your boiler has detected that there is not enough water circulating through the system, which can happen if there is a leak or if the internal pump has become stuck.
Check the pressure gauge on the front of the boiler; if it is below 1 bar, top up the system using the internal filling keyInspect visible radiator valves and pipework for any signs of water leaksReset the boiler by holding the reset button for five seconds once pressure is restored
Your boiler has lost its connection to the external heating controls or room thermostat, meaning it cannot receive the signal to turn on.
Check if your wireless thermostat has run out of batteries and replace them if necessary.Ensure the thermostat or programmer is switched on and within range of the boiler.Try resetting the boiler by holding the reset button for five seconds.
Your boiler has overheated because the water inside is getting too hot or is not flowing correctly, causing the system to shut down for safety.
Check if your system pressure gauge is below 1 bar and top it up if necessaryEnsure all radiator valves are fully open and there are no blockagesPress the reset button on the front of the boiler for five seconds
Your boiler is failing to light the flame needed to heat your water and radiators, which often happens when the gas supply is interrupted or a component is worn out.
Check if your gas meter has credit (if on a prepay meter).Check that your main gas lever/valve is turned to the 'on' position.Press and hold the reset button for five seconds to see if the boiler restarts.
Your boiler has sensed that the water inside it has become too hot and has shut down as a safety precaution.
Check that all radiator valves are fully open to allow water to circulate.Ensure your system pressure is between 1 and 1.5 bar on the pressure gauge.Gently bleed your radiators to remove any trapped air pockets.Reset the boiler by holding the reset button for five seconds.
Your boiler has stopped working because it cannot light the gas or keep the flame burning to provide heat.
Check if your gas credit has run out or if other gas appliances are working.Inspect the white condensate pipe outside for signs of freezing and thaw with warm water if iced up.Press and hold the 'Reset' button for five seconds to restart the ignition sequence.
on the Worcester Bosch Junior 24i
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