Flow's internal gas sensors work best if they remain in constant use. Your Flow has been designed to minimise loading times and maximise sensor efficiency. As Flow is designed to be a 24/7 air quality tracking device, it is not possible to turn it off.
If your Flow turns off because it's out of battery, you'll need to wait fifteen minutes for your sensors to warm up before you take a measurement. To avoid this as much as possible, make sure you keep the device charged up.