BoilerFaultCodesThe 6 most common faults
Your boiler has been manually reset too many times in a short period and has locked itself out as a safety precaution.
Turn the power supply to the boiler off at the fused spur switchWait for 30 secondsSwitch the power back on to clear the temporary software lock
Your boiler has detected that the water inside is getting too hot because it isn't moving through the system properly.
Check that all radiator valves are fully openEnsure the external heating pump (if visible) is runningCheck that the boiler pressure gauge is between 1.0 and 1.5 barReset the boiler once the system has cooled down
Your boiler has stopped working because the water level inside the heating system has dropped too low.
Locate the external filling loop, usually two silver valves connected by a small braided hose near the boiler pipes.Open the valves slowly to allow water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Fully close both valves and check the boiler for any leaks.
Your boiler has failed to light the flame properly and has safely shut itself down to prevent a gas build-up.
Full guide for Ignition LockoutYour boiler has failed to light the flame, so it has safely shut itself down to prevent a build-up of unburnt gas.
Full guide for 16Your boiler has detected that it is running too hot and has automatically turned itself off to prevent damage.
Full guide for Overheat Lockouton the Keston Heat 45
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