Unloader valve

Hi, I am having problems with my craftmen 2hp air compessor. When the pressure switch is in the auto position and reaches pressure, the switch hits the unloader valve and drains the tank until the next cycle. It also hits the unloader valve in the off position and totally drains the tank. I tried changing the pressure switch which included a new unloader valve and check valve but I still have the same problem. Do you have any ideas? Thanks, Travis Corning, NY