BoilerFaultCodesThe 6 most common faults
Your boiler is struggling to push water through your heating system because the water pressure inside is too low.
Check the pressure gauge on the front of your boiler; it should be between 1.0 and 1.5 bar.If the pressure is below 1.0 bar, locate the filling loop (usually two silver valves connected by a flexible hose underneath the boiler).Slowly open the valves to let water in until the needle reaches 1.5 bar, then close both valves tightly.
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's internal computer has encountered a communication error or technical glitch that is preventing it from running properly.
Locate the Reset button on the boiler control panelPress and hold the Reset button for three secondsWait for the boiler to restart and see if the fault code clears
Your boiler's internal computer has encountered a communication error or hardware fault and cannot operate correctly.
Press the Reset button on the front of the control panel for three secondsSwitch the main electrical power supply to the boiler off for 30 seconds and then back onContact a qualified engineer if the fault returns immediately after resetting
Your boiler has failed to set its internal flame settings correctly during a startup check and cannot run safely.
Press the 'Reset' button on the boiler control panel and hold for three seconds.Wait for the boiler to attempt the calibration process again.Ensure your gas supply is active by checking if other gas appliances in your home are working.
Your boiler's internal computer brain has detected a software or electronics error and has stopped working to protect itself.
Locate the reset button (represented by a flame with a line through it or the word 'Reset') on the front control panel.Press and hold the reset button for three seconds.Wait for the boiler to restart; if the code clears, monitor the boiler, but if it returns immediately, you will need a professional.
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
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
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