BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water pressure inside the heating system has dropped below the required level.
Locate the internal filling link (a silver lever or rotating valve) under the bottom of your boiler.Open the valve slowly to allow water into the system until the pressure gauge on the front display reaches between 1.0 and 1.5 bar.Close the valve tightly and check that the fault code clears from the display.
Your boiler has detected a fast leak in your radiator system, meaning it has lost water pressure too quickly for it to operate safely.
Check all radiators, valves, and exposed pipework for signs of wet patches or dripping water.Inspect the pressure relief pipe exiting through an external wall to see if it is leaking water outdoors.If no visible leaks are found, use the external filling loop to top the boiler pressure back up to 1.5 bar.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Locate the internal filling link or external filling loop beneath the boiler.Open the valves slowly to allow mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close the valves firmly and check that the fault code has cleared.
Your boiler is overheating because water isn't circulating through your radiators properly, likely due to low pressure or an issue with the internal pump.
Check your boiler pressure gauge; if it is below 1 bar, use the internal filling link or external filling loop to top the system up to between 1 and 1.5 bar.Walk around your home and ensure that all your radiator valves are fully open and not stuck shut.Restart your boiler using the reset button or power cycle to see if the pump clears its blockage.
Your boiler is shutting down because it cannot circulate water through your heating system, likely due to low pressure or a blockage.
Check your boiler pressure gauge to ensure it is between 1 and 1.5 barIf the pressure is low, use the external or internal filling loop to top the system upEnsure all radiator valves and any isolation valves near the boiler are fully open
Your boiler has detected that the water pressure in your heating system is falling away much faster than it should, causing it to shut down to protect itself.
Check your radiators and pipework throughout the house for any visible signs of water leaks or wet patches on the floor.Locate the external filling loop or internal key usually found underneath the boiler and open the valve slowly to reach the recommended pressure of 1.5 bar on the gauge.Monitor the pressure gauge over the next few hours to see if it drops again, which would confirm a persistent leak requiring a professional.
on the Worcester Bosch Greenstar 8000 Life System
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