Atag E11 Fault Code
The Atag E11 fault code means: your boiler's computer is experiencing an internal error and cannot safely operate your heating or hot water systems.. It appears on 1 Atag model in our database.
Technical description: Control unit fault
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Atag models that show the E11 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Atag E11 fault code information on this page is sourced and cross-checked against the official Atag service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026