BoilerFaultCodesThe 6 most common faults
Your boiler has detected that it is running without enough water inside, which is often caused by a leak or a pump that has jammed or failed.
Check the pressure gauge on the boiler and top it up to 1.5 bar using the filling loopInspect visible pipework and radiators for any signs of water leaksReset the boiler to see if the error clears after repressurising
Your boiler has switched itself off because it has detected that the water inside is getting too hot, likely due to a circulation problem or low pressure.
Check the pressure gauge on the front of the boiler; if it is below 1 bar, top it up using the filling loop.Ensure all radiator valves are fully open to allow water to flow freely.Gently press the small reset button located on the front control panel once the system has cooled down.
Your boiler has stopped working because it cannot light the flame, which is usually caused by a temporary interruption in the gas supply or a part that needs cleaning.
Check if you have credit on your gas meter.Verify that other gas appliances like your cooker are working.Press and hold the reset button for five seconds to see if the boiler restarts.
Your boiler has stopped working because the water inside has become far too hot, causing the system to shut down for safety.
Check that all radiator valves are fully open to allow water to circulate.Ensure the system pressure is between 1 and 1.5 bar on the pressure gauge.Press and hold the reset button for five seconds to see if the fault clears.
Your boiler has tried to light but cannot detect a flame, or the flame is going out shortly after starting, which has caused the system to stop working for safety.
Check if your gas supply is turned on at the meterCheck if any other gas appliances (like a hob) are working correctlyPress and hold the reset button for five secondsIn freezing weather, check if the white plastic condensate pipe outside is frozen and thaw it with warm water
Your boiler has detected an unexpected interruption or irregularity in its electrical power supply, which has caused it to stop working for safety.
Check if there has been a recent power cut or if a fuse has tripped in your home's consumer unit.Restart the boiler by pressing and holding the reset button for five seconds.Ensure the boiler's fused spur switch is fully turned on and hasn't been accidentally knocked.
on the Worcester Bosch Junior 28i
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