BoilerFaultCodesIntergas F08 Fault Code
The Intergas F08 fault code means: your boiler has stopped working because it cannot detect a stable signal from the sensor that monitors exhaust gases, often due to a loose wire or a faulty internal component.. It appears on 3 Intergas models in our database.
Technical description: Flue sensor open circuit
What causes the Intergas F08 fault?
This fault occurs when the boiler's control board loses communication with the sensor that monitors the temperature of the exhaust gases. It is usually caused by a wire vibrating loose over time, moisture affecting the electrical connections, or the sensor itself failing due to constant exposure to high heat. When this signal is lost, the boiler shuts down as a safety precaution to ensure it isn't venting gases at dangerous temperatures.
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 F08 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Intergas F08 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