VALVE INSTALLATION - When installing these 3 way diverter valves, you have to watch how they are positioned. These valve have three ports: two ends and one center. By design you can close off part of all of the water flow from either end ports, but you cannot shut off the center port. The handle will only rotate 180° on the side away opposite the center port. If this valve is installed incorrectly, as shown later, it is possible to inadvertantly shut off all water to the pump and run it dry. In this setup Valve 1 selects the flow from either the pool drain or the skimmer or both. Valve 2 selects the flow from the pool vacuum line or Valve 1.or both.