Beer has gas. If you set the CO2 pressure at the keg temperature (preferably 38F) but the temperature at the tower is 44F you will have a significant amount of waste when you attempt to dispense. The 38F beer will eventually chill this area and waste will cease. Unfortunately, this is called a beer chilled system. Search prior posts to find solutions to this issue.
Scott Zuhse, Instructor
Micro Matic Dispense Institute