Pentair whisperflo pump 1.5hp 3ph.
New pump installed in commercial facility, trying to prime it and it won't suck in the water. I have no back flow restrictions since the filter valve is on waste. All valves open on the suction side, the pump has suction, I checked the impeller. When I turn off the pump the water flows into the pump from the suction line on front. What could be happening here?