Occurrence of alarm 313 – “Buzzer test failed” in quiet environment has to be deeply analysed. Alarm 300 – “Device in failsafe” in combination with alarm 313 is a follow-up error. Whenever the ventilation is stopped (log-off) when alarm 313 is active, bellavista automatically performs a self-test. During the self-test, the software activates and resets alarm 300 three times to check bellavistas alarming system. That’s why alarm 300 can be found in the alarm log when alarm 313 has been active after the start-up and during a running ventilation.