I just came to ask the same question. Need the valve which does not require electricity and is controlled by the circuit network: http://puu.sh/uxWcE/4a4c6ca447.jpg
yeah, at least by circuit, if somehow possibly also by hand. What i belive is needed is some simple flow on/off valve for either early game, or just (roll credits) Flow Control without pumping. Sometimes pump is either unnecessary or there are no electricity around, or even there is no pump (early) to begin with (angel+bobmods). Valve would be AWESOME!