The number of times I have replaced the CU301 controller is staggering. Even on this forum the list is getting long. See this list from a search for CU301. http://www.terrylove.com/forums/sear...archid=1408221
The controller is trying to accomplish the same thing as the CSV. If you use both at the same time, they will be fighting each other. If your tank is still good, all you need is a CSV and a pressure switch. You should return the CU301 for a refund if possible. If it was a warranty replacement, maybe you can sell it on the Internet and pass the problem to someone else.
Use a little less air in the tank to make up for the soft start feature, ie. 40/60 switch, use 30 PSI air in the tank. Otherwise you will see a drop in pressure before the pump gets up and running.