my Jandy valve is only working in one position. It controls how much water comes from the pool drain or the pool skimmer into the filter/pump but now only works in the drain position. When turned to skimmer position it won't suck water/prime when turning pump from off to on but if I set it to Drain, it will prime itself. If I then quickly turn to Skimmer it then sucks water but also a lot of air. The pressure is about 14 lbs from Drain but 2-3 from skimmer when doing this. Is this a Jandy valve problem, or something else?