BoilerFaultCodesIntergas E12 Fault Code
The Intergas E12 fault code means: your boiler's hot water sensor has failed or detected an error, meaning the system cannot accurately measure the temperature of your tap water.. It appears on 6 Intergas models in our database.
Technical description: DHW sensor S3 defective
What causes the Intergas E12 fault?
This fault occurs when the domestic hot water sensor becomes damaged or begins sending incorrect electrical signals back to the main control board. The most common reason is internal wear and tear on the sensor's thermistor, though loose wiring or moisture ingress at the connection point can also trigger the error.
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 E12 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Intergas E12 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