BoilerFaultCodesAriston 104 Fault Code
The Ariston 104 fault code means: your boiler is struggling to circulate water properly, which is preventing it from heating up safely.. It appears on 1 Ariston model in our database.
Technical description: All Boilers
DIY fix possible
Check that your boiler pressure is between 1 and 1.5 bar on the display.If the pressure is low, use the filling loop to top it up.Ensure all radiator valves and isolation valves under the boiler are fully open.Reset the boiler after checking these steps.
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Gas Safe Register →Ariston models that show the 104 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ariston 104 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 27 April 2026