BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because it cannot detect a flame, meaning it has safely shut down to prevent issues.
Check if other gas appliances, like a hob, are working to ensure gas is reaching the property.Ensure your credit is topped up if you have a prepaid gas meter.Gently press the 'Reset' button (marked with a flame or cross symbol) and hold for 2 seconds.
Your boiler has detected a general operational error or a loss of flame, causing it to stop providing heating and hot water.
Check if your gas prepay meter has creditCheck if other gas appliances in the house are workingPress and hold the reset button (indicated by a flame with a line through it) for five seconds
Your boiler is not receiving enough gas or is struggling to light the flame properly.
Check that your gas meter has credit and the emergency control valve is openSearch for other gas appliances in your home, like a hob, to see if they are workingPress the 'Reset' button (marked with a flame or 'R') on the boiler control panel
Your boiler has likely lost water pressure or there is a blockage preventing water from circulating properly, causing the system to stop heating.
Check the pressure gauge on the front of the boiler; if it is below 1.0 bar, you need to top it up.Locate the filling loop underneath the boiler and slowly turn the valves until the pressure reaches 1.5 bar.Ensure all radiator valves are open and that your pump is running if accessible.
Your boiler has lost power or has a serious internal communication error, meaning it cannot operate or tell you what is wrong.
Check if the main boiler power switch or fused spur is turned onCheck your home's consumer unit (fuse box) to see if a circuit breaker has trippedEnsure the power cable leading into the bottom of the boiler is securely connected
Your boiler is overheating because the water is not flowing through the system quickly enough or the temperature is rising too fast.
Check that your boiler pressure is between 1.0 and 1.5 bar on the gaugeEnsure all radiator valves are fully open to allow water flowTry resetting the boiler using the flame/reset button
on the Glow-worm 30cxi
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 Glow-worm 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