BoilerFaultCodesThe 6 most common faults
Your boiler has failed to light after several attempts and has stopped for safety, meaning you currently have no heating or hot water.
Check if other gas appliances, like a hob, are working to confirm gas supplyCheck that your gas meter has credit if you use a prepay meterPress the Reset button once to see if the boiler restarts
Your boiler has been manually reset too many times in a short window and has temporarily locked itself to prevent potential damage or unsafe operation.
Turn off the power supply to the boiler at the fused spur switch (the wall switch).Wait approximately 30 seconds.Turn the power back on to clear the lockout memory and see if the boiler resumes normal operation.
Your boiler has detected that there is not enough water in the system to operate safely, which is usually caused by a small leak or air being bled from radiators.
Locate the filling loop (usually a silver flexible hose) underneath or near the boiler.Slowly open the one or two taps/valves until you hear water flowing.Watch the pressure gauge until it reaches between 1.0 and 1.5 bar, then close the taps tightly.
Your boiler has stopped working because it cannot detect water moving through the system to keep it cool and functioning safely.
Check that your boiler pressure gauge is between 1.0 and 1.5 bar.Ensure all radiator valves and isolation valves under the boiler are fully open.Gently bleed your radiators to remove any trapped air pockets.Restart the boiler using the reset button once pressure is confirmed.
Your boiler has shut itself down because the water inside has become too hot, which is a safety measure to prevent damage.
Check that your radiator valves/TRVs are open to allow water to flow.Check the boiler pressure gauge and top up to 1.5 bar if it is low.Banish any trapped air by bleeding your radiators.Press the Reset button once the boiler has had 15 minutes to cool down.
Your boiler has switched itself off to prevent damage because the internal water temperature has become too hot.
Check the pressure gauge and top up to 1.0 bar if it is lowEnsure all radiator valves are fully openBleed any air out of the radiators and reset the boiler
on the Keston 30C
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 Keston 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