BoilerFaultCodesAriston B08 Fault Code
The Ariston B08 fault code means: your boiler's built-in timer or clock has encountered a communication error, meaning the heating may not turn on at your scheduled times.. It appears on 3 Ariston models in our database.
Technical description: Time Clock
DIY fix possible
Check the clock settings to ensure they haven't been accidentally clearedRotate the timer pins or digital settings to 'On' to see if the boiler firesPerform a simple reset of the boiler using the 'R' or reset button
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Ariston models that show the B08 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ariston B08 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