BoilerFaultCodesViessmann E11 Fault Code
The Viessmann E11 fault code means: your boiler has stopped working because its internal computer board has detected a serious electronic error.. It appears on 1 Viessmann model in our database.
Technical description: Control unit fault. Internal error.
What causes the Viessmann E11 fault?
This fault occurs when the boiler's main control board experiences a critical hardware failure or a communication error between its internal electronics. The most common reason is a component failure on the PCB itself, often caused by age, electrical surges, or moisture ingress from a small leak. It effectively means the boiler’s 'brain' can no longer safely manage the heating process, so it shuts down as a 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 →Viessmann models that show the E11 fault code
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Source
Viessmann E11 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026