I have the Krystal Clear Sand Filter Pump 14", model SF15110. This is its 2nd season of use, last year worked fine. It is connected to a 16' round metal-frame Intex pool. The pump has a 6-way handle. When I connected it this year I notice that it does not pump water from the inlet to the outlet when the handle is set to Filtration. There are no clogs and everything is connected correctly. If I set the handle to Recirculate, which reverse the flow, the water moves correctly. If the pump is turned off and I discounted the outlet from the pool, water flows out, so I know it can make it from the inlet to the outlet, its only when the pump is in Filtration setting that the water does not flow. Any ideas?