Your boiler has failed its routine high-temperature anti-bacteria cycle for the hot water system, meaning the water did not reach the required sterilization temperature.

Hot water heating: thermal disinfection failed: 1. Possibly prevent continuous water withdrawal. 2. Positioning the hot water sensor correctly. 3. Set domestic hot water preparation to “Priority”. 4. Possibly vent. 5. In the event of faults in the piping, rectify them. 6. If there are deviations: replace the pump. 7. Check circulation pipe. 8. In case of deviations from the table values: replace the sensor.