BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Locate the filling loop (a silver flexible hose) underneath the boiler.Open the small valve or tap on the loop to allow mains water into the boiler.Monitor the pressure gauge on the front until it reaches 1.5 bar, then turn the valve firmly off.
Your boiler is struggling to move water around the system fast enough, likely due to low water pressure or a blockage.
Check your boiler pressure gauge; if it is below 1 bar, use the filling loop to top it up to 1.5 barEnsure all radiator valves are fully openTurn the boiler off and back on again to reset the temporary fault
Your boiler has detected that there is not enough water pressure in the system to operate safely, which has caused it to shut down.
Locate the filling loop (the silver flexible hose) underneath your boiler.Open the two valves slowly to allow water into the system.Watch the pressure gauge and close the valves once it reaches between 1.0 and 1.5 bar.
Your boiler has tried to light several times but has been unable to sustain a flame, meaning you will have no heating or hot water until it is reset.
Check if your gas meter has credit or other gas appliances are workingEnsure the gas isolation valve under the boiler is fully openPress and hold the 'Reset' button (the one with the flame symbol) for 2-3 seconds
Your boiler is trying to start but the flame is not catching, meaning it cannot provide you with heating or hot water.
Full guide for F28Your boiler has lost the ability to measure the temperature of the water being sent to your radiators, so it has shut down as a precaution to prevent overheating.
Full guide for F00on the Heatline Vizo 24
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 Heatline 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