on Low

Ariston on Fault Code

Also written as ON — same fault.

The Ariston on fault code means: your boiler is correctly powered on and is currently in standby mode or ready to provide heating and hot water.. It appears on 1 Ariston model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: The boiler is powered on

DIY fix possible

This fault may be fixable without an engineer. Check your manual first.

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Ariston models that show the on fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ariston on 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