BoilerFaultCodesThe 6 most common faults
Your boiler has detected that hot water isn't moving around your system properly, likely due to low water pressure or trapped air, causing the unit to shut down to prevent overheating.
Check the pressure gauge on the front of the boiler; if it is below 1 bar, locate the filling loop underneath the unit.Open the filling loop to allow water into the system until the gauge reads between 1.2 and 1.5 bar.Once repressurized, reset the boiler and check if the error clears.
Your boiler is struggling to move water around your heating system correctly, which is preventing it from heating your home or water efficiently.
Check your thermostat and heating programmer are set to 'on'.Ensure all radiator valves are fully open.Check your boiler pressure gauge to confirm it is between 1.0 and 1.5 bar; if low, use the filling loop to top it up.
Your boiler is struggling to move enough water through its internal system to heat your home properly.
Check your boiler's pressure gauge to ensure it is between 1 and 1.5 barIf the pressure is low, locate the filling loop and add water until it reaches the correct levelEnsure all radiator valves in your home are fully open to allow water to flow freely
Your boiler has detected that the water pressure inside the system is too low for it to operate safely and effectively.
Locate the filling loop, which is usually a flexible silver braided hose with one or two small valves underneath the boiler.Open the valve(s) slowly to allow water into the system while watching the pressure gauge on the front panel.Stop filling when the needle reaches the green zone, typically between 1.0 and 1.5 bar, then ensure the valves are tightly closed.
Your boiler has stopped working because it cannot light the internal burner or keep it burning.
Full guide for 5 01Your boiler has detected an issue with the internal combustion process, preventing it from starting up or maintaining a flame.
Full guide for 591on the Ariston E-Combi Evo
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