I say it's definitely open only because it flows fine at low pressure. If I disconnect the hoses from the pressurized line, I can blow/suck through the valve. I also have a diaphragm (aquarium) pump which can pump a steady amount of liquid through the valve just fine.
I guess it's more like 40-45 PSI, but still.
If this valve doesn't work because the high pressure is jamming it shut or something that's fine, in fact I am using it for other purposes and just grabbed it as a test. But I would like to know what I need to purchase in order to get this setup to work properly??
Thanks again!