BoilerFaultCodesAriston Insufficient System Pressure Fault Code
Also written as INSUFFICIENTSYSTEMPRESSURE — same fault.
The Ariston Insufficient System Pressure fault code means: your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.. It appears on 1 Ariston model in our database.
Technical description: Shutdown occurs in the event of insufficient water pressure in the heating system (less than 0.4 bar). Resets automatically once pressure reaches 1.5 bar.
DIY fix possible
Locate the flexible silver filling loop underneath or near your boiler.Slowly open the small tap(s) on the loop to allow water into the system.Watch the pressure gauge and close the taps firmly once it reaches 1.5 bar.
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Ariston models that show the Insufficient System Pressure fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ariston Insufficient System Pressure 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 7 July 2026