By default, all Chromeboxes automatically go to sleep if left inactive for 8 minutes. And while you can adjust the brightness level of the screen, you cannot tweak display timeout settings on Chrome OS. That is, you cannot do so without a Chrome Extension, like Keep Awake. By following these instructions, you’ll be able to keep your Chromebook from going to sleep.
Keep Awake is installed by the FCIT Department so you will find a tiny moon will appear on the right side of your Chrome browser toolbar. As long as the moon is the icon, the Chromebox’s display settings will remain unchanged.
Tap the moon to change it into a little sun, which indicates that the Chromebox will not go to sleep.