How much does it cost to fix Ariston error code Overheat thermostat?

Typical repair cost for the Ariston Overheat thermostat fault is £120-250 including labour.

Overheat thermostat High

Ariston Overheat thermostat Fault Code

Q: What does the Ariston Overheat thermostat fault code mean?

Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.

Also written as OVERHEATTHERMOSTAT — same fault.

The Ariston Overheat thermostat fault code means: your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.. It appears on 3 Ariston models in our database.

Technical description: Safety thermostat intervention; can be caused by C.H./D.H.W. temperature probes open circuit, thermostat calibration, or air in primary water circuit.

Typical repair cost £120-250 (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 Overheat thermostat fault code

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

Source

Ariston Overheat thermostat 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