In my research for a new pump I stumbled across this users manual from Reeflo.
http://www.reeflopumps.com/dimsmanuals.html
ALL OF OUR PUMPS CAN BE "VALVED BACK" AS LONG AS ITS DONE ON THE DISCHARGE LINE. IT WILL NOT ONLY REDUCE THE FLOW, IT WILL LOWER THE WATT USAGE AND EXTEND THE LIFE OF THE MOTOR AND SEAL!
http://www.reeflopumps.com/dimsmanuals.html
ALL OF OUR PUMPS CAN BE "VALVED BACK" AS LONG AS ITS DONE ON THE DISCHARGE LINE. IT WILL NOT ONLY REDUCE THE FLOW, IT WILL LOWER THE WATT USAGE AND EXTEND THE LIFE OF THE MOTOR AND SEAL!