How much does it cost to fix Ariston error code E 12?

Typical repair cost for the Ariston E 12 fault is £120-220 including labour.

E 12 High

Ariston E 12 Fault Code

Q: What does the Ariston E 12 fault code mean?

Your boiler is struggling to detect the flow of water because of a faulty electronic sensor, which will prevent your heating and hot water from working correctly.

Also written as E12 — same fault.

The Ariston E 12 fault code means: your boiler is struggling to detect the flow of water because of a faulty electronic sensor, which will prevent your heating and hot water from working correctly.. It appears on 2 Ariston models in our database.

Technical description: Flow sensor short circuit

Typical repair cost £120-220 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Ariston models that show the E 12 fault code

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

Source

Ariston E 12 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