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L era //du J F,Q <br />F-15 <br />PUMP SELECTION PROCEDURE <br />A. Determine pump capacity: <br />1. Minimum suggested is 600 gallons per hour (10 Rpm) - <br />to stay ahead of water use rate <br />2. Maximum suggested for delivery to a drop box of a home <br />system is 2700 gallons per hour (45 gpm) to prevent ^ <br />buildup of pressure in drop box <br />3. Use value from design of pressure distribution system f� <br />SELECTED PUMP CAPACITY . . . . . . . . . . . . . . . . _ —5- <br />gp <br />B. Determine head requirements: <br />I. Elevation difference between pump and point of discharge <br />-feet <br />2. If pumping to a pressure distribution system, add 5 feet <br />for pressure required at manifold . . . . . . . . . . <br />.S feet <br />3. Friction loss <br />a. Enter Enter friction loss table with gpm and pipe diameter. <br />Read friction loss in feet per 100 feet from page F-18. <br />F. L. = ft/100 ft <br />b. Determine total pipe length from pump to discharge <br />point. Add 25 percent to pipe length for fitting <br />loss, or use a fitting loss chart. Equivalent pipe <br />length - 1.25 times pipe length = 1.25 x O <br />!D O fret <br />_� <br />C. Calculate total friction loss by multiplying -- <br />e <br />friction loss In ft/100 ft by equivalent pine <br />length. <br />Total friction loss a 7 1Y x /Z 0 - <br />/._/_ feet <br />4. Total head required is the sum of elevation difference, <br />special head requirements, and totc.l friction loss. <br />y + s + 7. <br />TOTAL HEAD . . . . . . . . . . . . . . . . . . . . . <br />/6. / feet <br />C. Pump selection H� <br />I. A pump must be selected Eo deliver at least J S; i gpm <br />with at least /6. / feet of total head. <br />D. To maximize pump life select sump size for 4 to 5 pump <br />operations per day. <br />I•:. Calculate drainback <br />1. Determine total Ripe length, a o feet. <br />2. Determine liquid volume of pipe, �, S,Q gallons per <br />100 feet. (See page F-18) <br />3. Multiply length by volume: Drainback quantity = <br />8'0 feet x a, S F gallons/100 ft - S_.5 gallons <br />4. Suggested drainback quantity is 10 percent of pumped quantity. <br />A larger drainback percentage will decrease pump station <br />efficiency slightly but pumping energy costs are usually a <br />relatively small part of the total household energy costs. <br />