BoilerFaultCodesThe 6 most common faults
Your boiler's computer system has encountered a logic error and needs to be restarted to clear the fault.
Locate your boiler's reset buttonPress and hold the reset button for 3 to 5 secondsWait for the boiler to reboot and check if the error code clears
Your boiler is struggling to push water around your heating system because the internal water pressure is too low or the pump is failing to detect movement.
Check your boiler pressure gauge; if it is below 1 bar, locate the filling loop and add water until it reaches 1.5 barTurn the boiler off at the fused spur for 30 seconds and then switch it back on to reset the systemEnsure all radiator valves are fully open to allow for proper flow
Your boiler has stopped working because the water pressure inside your heating system has dropped below the required level.
Locate the filling loop (a silver flexi-hose) or the internal key under the boilerSlowly open the valves to allow water from the mains into the systemWatch the pressure gauge on the front of the boiler until it reaches the green zone (usually 1.5 bar)Close the valves firmly to stop the flow
Your boiler has experienced a memory or software error and needs to be restarted to restore its original settings.
Locate the 'Reset' button on the boiler control panel.Press and hold the Reset button for 3 to 5 seconds.Wait for the boiler to complete its restart sequence and check if the display returns to normal.
Your boiler has likely overheated, causing it to shut down as a safety precaution to prevent damage.
Check that your radiator valves are open to allow water to flow.Check the boiler pressure gauge and top up to 1.5 bar if it is too low.Press and hold the 'Reset' button on the front of the boiler for three seconds.
Your boiler has detected that the water temperature has exceeded the maximum safe limit, causing it to shut down to prevent damage.
Check that all radiator valves (TRVs) are turned to the maximum setting.Ensure the boiler pressure is within the green zone (usually 1 to 1.5 bar).Check if the magnetic system filter is blocked or needs cleaning.
on the Worcester Bosch Greenstar 2000
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