304 Medium

Ariston 304 Fault Code

The Ariston 304 fault code means: your boiler has attempted to restart itself too many times in a short period and has temporarily locked you out for safety.. It appears on 1 Ariston model in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: All Boilers
Typical repair cost £0-120 (including labour)

DIY fix possible

Locate the Reset button on the front control panel.Press and hold the Reset button for 5 seconds.Wait for the boiler to complete its restart sequence.If the code persists, check if other gas appliances are working.

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Ariston models that show the 304 fault code

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

Source

Ariston 304 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