BoilerFaultCodesThe 6 most common faults
Your boiler is struggling to push water around your heating system because the flow is too slow or blocked.
Check that all your radiator valves are fully openEnsure the system pressure is between 1.0 and 1.5 bar on the boiler gaugeBleed your radiators to remove any trapped air that might be blocking the flow
Your boiler is struggling to move enough water through its system, which is often caused by low pressure or trapped air in the radiators.
Check your boiler's pressure gauge and ensure it is between 1 and 1.5 barBleed all radiators in the house to release any trapped airCheck that all radiator valves are fully open
Your boiler is struggling to push water around your heating system, usually because there is air trapped inside or the pressure is too low.
Check your boiler display to ensure the pressure gauge reads between 1.0 and 1.5 bar.If the pressure is below 1 bar, use your external filling loop to top it up to the correct level.Bleed your radiators using a radiator key to release any trapped air and then re-check the pressure.
Your boiler is struggling to push water around your heating system, likely due to a blockage or a pump issue, which has caused it to stop heating.
Check that all radiator valves throughout your home are fully openEnsure the system pressure is set to approximately 1.5 barBleed your radiators to release any trapped air and then top up the system pressure if needed
Your boiler is struggling to pump water around your heating system correctly, which is likely due to low pressure or a blockage.
Check your boiler pressure gauge and ensure it is between 1.0 and 1.5 barIf the pressure is low, use the filling loop to top it up to the required levelCheck that all your radiator valves are fully open to allow water to flow freely
Your boiler is struggling to move water around your heating system effectively, preventing it from heating your home properly.
Check your radiator valves are fully openEnsure your system pressure is at the recommended level, typically between 1 and 1.5 barBleed your radiators to remove any trapped air that may be blocking the water flow
on the Ariston Clas HE R
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 Ariston 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