compressor questions

[ERASER5]

I'll not argue weather or not that pipe is and un-loader, maybe it unloads something else but the HEAD un-loader is clearly seen and hooked up. The small tube leaving the pressure control switch and T-ed into the large copper pipe from the compressor to the tank. Inside the controller is a long needle shrader valve that is opened during cut off. The pressure in the head and that large copper tube is bled off (the hiss you hear after shutoff). The shrader is closed on start up and there is no head pressure for easy start. That big tube and T and screwed into a check valve recessed into the tank. Standard compressor setup.