BoilerFaultCodesIntergas E27 Fault Code
The Intergas E27 fault code means: your boiler is having trouble reading the outside temperature and is unable to adjust your heating efficiently.. It appears on 6 Intergas models in our database.
Technical description: Outside sensor S5 defective
What causes the Intergas E27 fault?
This fault occurs when the boiler loses communication with the sensor installed on your outside wall, which usually means the sensor has developed an internal electrical fault. It is often caused by moisture getting into the sensor housing or a break in the thin wiring that connects the sensor to your boiler. Without this data, the boiler cannot automatically adjust its temperature based on the weather outside.
This fault is more common during autumn and winter when heavy rain and frost can cause corrosion or moisture ingress within the external sensor unit.
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 E27 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Intergas E27 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