Air in Skimmer Line

[desertrat]

I have an inground pool with water flow into the pump from a floor drain line and a skimmer. I can select either one separate or both using a Jandy valve. The floor drain side alone gives good pressuresand flows with no air in the lines. When I switch to the skimmer side only I get no flow or simply sporadic flow with an occasional gush of water and no pressure. I just replaced all the orings on the Jandy valve. Also, when I remove the Jandy valve and put a water hose in the skimmer side I see flow coming into the skimmer. Yet I put all back together and same problem. No flow from skimmer side. When I set the Jandy valve in the middle I just suck a bunch of air, same as with skimmer alone.