Not enough pressure to allow free flow on the one side. When fully open, water flows in both directions. When fully closed, water does not flow from any direction.get a water source and put it in one end and turn the valve down tell the colors are gone. turn the value open and you should see the water flow out the other end
Got it homie. Thanks for the info!the side with the slow down knob is closes to is your pressure side which is on your in let the other side s your out which would hook up to your dump , which means your left side or input side is the controlled side i hope this is not confusing to you.