BoilerFaultCodesAriston E05 Fault Code
The Ariston E05 fault code means: your boiler has detected that the water inside the system is getting too cold and has switched on its internal pump to keep the water moving and prevent freezing.. It appears on 6 Ariston models in our database.
Technical description: Anti-freeze system, pump only
DIY fix possible
Ensure power to the boiler remains switched onCheck that the gas supply is activeEnsure the system pressure is between 1.0 and 1.5 barKeep internal doors open if the boiler is in a particularly cold area like a garage
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Ariston models that show the E05 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ariston E05 fault code information on this page is sourced and cross-checked against the official Ariston service / installation manuals for each affected model.
- Ariston Bravo 24 MFFI manual (PDF)
- Ariston Micro Condens manual (PDF)
- Ariston Genus 24 Rffi manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026