This is simple procedure my friend, After you are don charging you close off the tank, then you turn off the discharge service port valve, then you open your high side manifold valve, then slowely open the low side manifold valve and allow the system to pump out your hoses. If you front seat the suction service valve you can actualy pull your hoses right down to 0psi.
Figured it out already, however he does not have a valve on the highside to close off the schraeder or such.