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 detected that the water inside the unit is getting too hot, so it has safely shut itself down to prevent damage.
Full guide for 204Your boiler is shutting down because it is heating up much faster than it can circulate the water, which often points to a blockage or a pump issue.
Full guide for 212Your boiler has stopped working because it detected a problem with the internal fan that pushes exhaust gases out of your home.
Full guide for 214on the Worcester Bosch Greenstar 28CDi
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