BoilerFaultCodesKeston E11 Fault Code
The Keston E11 fault code means: your boiler has stopped working because its internal sensors are reporting conflicting temperature readings that don't match up during a self-test.. It appears on 9 Keston models in our database.
Technical description: The automatic test for calibration of flow and return sensors has failed – check both flow and return sensors are located on the correct pipes and are producing the correct readings
What causes the Keston E11 fault?
This fault occurs when the boiler's control chip detects that the temperature sensors on the outgoing and incoming pipes are giving contradictory information during a startup check. The most common reason is that one of the sensors has drifted out of calibration or has been physically loosened from its pipe, meaning the boiler can no longer safely calculate how much heat it is generating. In some cases, it can also be caused by a faulty wiring connection preventing the signals from reaching the main circuit board correctly.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Keston models that show the E11 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Keston E11 fault code information on this page is sourced and cross-checked against the official Keston service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026