BoilerFaultCodesIntergas F11 Fault Code
The Intergas F11 fault code means: your boiler has stopped working because one of its internal temperature sensors has lost its electrical connection or developed a fault.. It appears on 3 Intergas models in our database.
Technical description: Return sensor open circuit
What causes the Intergas F11 fault?
This fault occurs when the boiler's control board loses communication with the sensor that monitors the temperature of the water returning from your radiators. This is usually caused by the internal sensor failing electrically or a connection point within the wiring becoming loose or damaged over time. Because the boiler can no longer safely track how much heat is in the system, it shuts down as a safety precaution.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Intergas models that show the F11 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Intergas F11 fault code information on this page is sourced and cross-checked against the official Intergas service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026