How much does it cost to fix Ariston error code E09?

Typical repair cost for the Ariston E09 fault is £120-200 including labour.

E09 High

Ariston E09 Fault Code

Q: What does the Ariston E09 fault code mean?

Your boiler's internal sensor that monitors the water temperature returning to the system is reading incorrectly, causing the unit to shut down for safety.

The Ariston E09 fault code means: your boiler's internal sensor that monitors the water temperature returning to the system is reading incorrectly, causing the unit to shut down for safety.. It appears on 1 Ariston model in our database.

Technical description: Heating return temperature probe short circuited

Typical repair cost £120-200 (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 E09 fault code

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

Clas One Repair: £120-200

Source

Ariston E09 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