BoilerFaultCodesBuderus CA Fault Code
The Buderus CA fault code means: your boiler has detected that the water returning to the unit is much too hot, causing it to shut down for safety.. It appears on 1 Buderus model in our database.
Technical description: Blinking fault code: Return sensor exceeds 105 °C
DIY fix possible
Check that all radiator valves are fully openEnsure the boiler pressure is between 1 and 1.5 barRestart the boiler to see if the error clears
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Buderus models that show the CA fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Buderus CA fault code information on this page is sourced and cross-checked against the official Buderus service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026