BoilerFaultCodesAriston A 02 Fault Code
Also written as A02 — same fault.
The Ariston A 02 fault code means: your boiler has stopped working because the water pressure inside the heating system has dropped too low.. It appears on 2 Ariston models in our database.
Technical description: check the pressure gauge to see if the water pressure in the appliance is 1 bar
DIY fix possible
Locate the filling loop (a silver flexi-hose with one or two valves) underneath the boiler.Open the valves slowly to allow mains cold water into the system until the pressure gauge reads between 1 and 1.5 bar.Close the valves tightly and check the boiler display to see if the error has cleared.
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Ariston models that show the A 02 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ariston A 02 fault code information on this page is sourced and cross-checked against the official Ariston service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026