[feverittm]

Please post another set of pictures from your connections. It might be helpful.

If you pressurize the system on the compressor side of the regulator to 100psi and set the regulator to 40psi. Will the system hold pressure? How long?

Pressure input in the 'P' port, leave exhaust ports open, make sure all output ports are either plugged or connected to a cylinder (ports go vertical on the manifold).

If you can get it to hold pressure. Press the manual button and the cylinder should move. If you let go of the button it should go back to the original position.

You need to make sure you keep enough pressure on the valve or it won't work. And make sure that when you activate the valve you don't lose all your pressure. If you do as others have said, something isn't hooked up right.