If I just run the water in the sink after about 15 seconds the water starts to backup into the basin. If I turn on the Insinkerator Evolution Cover Control Plus disposal it spins and runs fine. The sink will eventually drain, but it takes 40-60 minutes. I have already pulled apart the PVC drain lines and they are all free and clear. I briefly tried using a plunger, but that didn't change anything... I do have a dishwasher that drains to this, so I think the dishwasher drain line might have prevented me from truly having a closed circuit. I welcome your advice.