BoilerFaultCodesAriston Overheat thermostat Fault Code
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 2 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.
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 7 July 2026