BoilerFaultCodesThe 6 most common faults
Your boiler is struggling to move enough water through your radiators, which prevents it from heating your home safely.
Check your radiator valves to ensure they are all in the 'open' positionCheck the central heating system pressure gauge on the front of the boiler to ensure it is between 1.0 and 1.5 barIf the pressure is low, locate the filling loop under the boiler and top up the system to 1.5 bar
Your boiler has detected that water is not moving through your heating system correctly, which is preventing it from heating your home properly.
Check all radiator valves in your home are fully open.Ensure your system pressure is set correctly, typically between 1.0 and 1.5 bar on the gauge.Turn the boiler off at the fused spur for 30 seconds and then back on to reset the system.
Your boiler is struggling to push water through your heating system effectively, preventing it from heating your home or water properly.
Check that all your radiator valves are fully openEnsure your system pressure is between 1.0 and 1.5 bar on the boiler displayBleed your radiators to release any trapped airTurn the boiler off and back on again to reset the system
Your boiler is struggling to move enough water through your radiators or pipes, preventing it from heating your home property.
Check all radiator valves are fully openEnsure your system pressure gauge is between 1 and 1.5 barBleed all radiators to release trapped air trapped in the system
Your boiler has detected that the water pressure inside the system has dropped too low to operate safely.
Locate the external filling loop or internal filling valve underneath the boiler.Gradually open the valve until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.Close the valve tightly and ensure the boiler resets itself or press the reset button.
Your boiler has detected that the water pressure inside your heating system is too high, which can cause internal leaks or force the safety valve to open.
Locate the external heating system drain valve near a low-level radiator.Place a bucket and cloth underneath, then slowly open the valve to release a small amount of water.Monitor the boiler's pressure gauge until it drops into the green zone (usually 1.5 bar) and close the valve tightly.
on the Ariston Clas Net One
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