EDIT - just looked at your picture of your setup, if you can't get it to draw through any setting on your valve, your issue is MOST LIKELY somewhere between the valve and the pump.
That leaves you an area of about 10 inches to investigate - should not be too tough to do, disconnect the pump and look into the line to the valve, switch the valve and look to see if it even moved, maybe the valve is toast.
Looks like the valve is relatively easy to dissassemble as well, at worst you should be able to take it appart to reach what's causing your problem.
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