BoilerFaultCodesAtag 110 Fault Code
The Atag 110 fault code means: your boiler has switched itself off because it detected that the internal water temperature has become dangerously hot or a sensor has failed.. It appears on 5 Atag models in our database.
Technical description: Safety temperature exceeded / send probe damaged
DIY fix possible
Ensure all radiator valves are fully open to allow water to flow.Check that your boiler pressure is between 1 and 1.5 bar on the pressure gauge.Turn the boiler off and back on again once it has had 30 minutes to cool down.
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Atag models that show the 110 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Atag 110 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 7 July 2026