The screen is there to show you the temperature of the keg, how many days of freshness it has left and the volume of beer left. If the screen on your machine doesn't look quite right, go through this checklist and if you are still unsure, just get in touch!
Is the tap pushed down correctly on the keg? If the machine doesn't detect a keg attached the screen won't work
Remove the tap unit, clean it and reinstall. If this doesn't help try another keg with a new tube
Make sure when you install a new keg you reset the day counter on the screen to 30 days. To do this use the + and - buttons under the screen. Otherwise once it goes past 30 days a red ! will appear