BoilerFaultCodesSaunier Duval F10 Fault Code
The Saunier Duval F10 fault code means: your boiler has detected a problem with the sensor that monitors the temperature of the water returning to the unit, which has caused the heating to stop working.. It appears on 3 Saunier Duval models in our database.
Technical description: Central heating return thermistor fault. Thermistor cable defective/broken, thermistor faulty. Check that thermistor attached correctly to pipe
What causes the Saunier Duval F10 fault?
This fault occurs when the boiler's control board loses communication with the sensor that measures the temperature of the water coming back from your radiators. The most common reason is that the internal components of the sensor have failed due to age, or the electrical wiring connecting it to the main computer has become loose or damaged.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Saunier Duval models that show the F10 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Saunier Duval F10 fault code information on this page is sourced and cross-checked against the official Saunier Duval service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026