I ordered 2 machines. One of them was making a very slight grinding noise, even in Auto mode and not oscillating. I wouldn’t even have suspected a fault except the 2nd machine was totally silent. I called Support, described the problem and they exchanged the machine immediately, no questions asked. The whole return process was simple, quick and transparent

After fiddling with all the controls for a week or so I discovered the best protocol is simply to leave it in Auto mode.  I love to keep an eye on the pollutant levels through the app and see the machine adapt to the conditions. Love it