wiring asco/stc electric valve

[JSomps6]

So I have an STC Electronic Valve (same as an ASCO) and I need to wire it up. I bought it on ebay and it did not come with a wiring diagram or anything like that. There are 3 ports to connect wires, however they are not marked as + or -. I believe I know which one is the ground. Is there a way to test which is which? If I just hook it up and try it, would I risk hurting anything? I'm thinking if it's backwards it will just be open when it should be closed? I want to try it, but want to make sure I won't mess anything up if I get it wrong. Can anyone help me out here? Thanks!

 

[kladue]

If you have the square connector (Din) then there are 3 terminals, Left side(power), Center (ground), right side (return, or neutral). To open one up pull the screw and push the center portion that screw went through to pop contact block out, does not work so well if retaining screw is not removed For DC there does not seem to be any polarity preferences in the literature, so either side can be power/return. For the Asco valves there are 2 red colored wires for power and return, and a yellow striped green wire for coil ground with some models of coils.