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/ <br />* <br />■% <br />/V* crz^/u/ <br />/>!< ^ £ff4^4foa/^ <br />PUMP SELECTION PROCEDURE <br />F-15 <br />A. Determine pump capacity: <br />1. <br />2. <br />3. <br />Minimum suggested Is 600 gallons per hour (10 gpm) - <br />to stay ahead of water use rate <br />Maximum suggested for delivery to a drop box of a home <br />system Is 2700 gallons per hour (43 gpm) to prevent <br />buildup of pressure In drop box <br />Use value from design of pressure distribution system <br />SELECTED PUMP CAPACITY gpm <br />B. Determine head requirements: <br />1. <br />2. <br />3. <br />4. <br />Elevation difference between pump and point of discharge _ <br />If pumping to a pressure distribution system, add 5 feet <br />for pressure required at manifold . . . . . . . . . . . . . <br />Friction loss <br />a. 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_/70t * <br />c. Calculate total friction loss by multiplying <br />friction lo.s8 in ft/100 ft by equivalent pipe <br />length. <br />Total friction loss • V. o3/tAn x Z.iZ t ■ <br />Total head required is the sum of elevation difference* <br />special head requirements, and total friction loss. <br />+ s ^ r. 5 <br />t feet <br />ZUt feet <br />S t feet <br />TOTAL HFJU). . . . . . . . . . . . . . . . . . . . . . . . . . . <br />C. Pump selection <br />1. A pump must be selected to deliver at least € gpm <br />with at least t feet of total head. <br />D. To maximize pump life select sump size for 4 to 5 pump <br />operations per day. <br />2J.St feet <br />K. Calculate drainback <br />1. <br />2. <br />3. <br />4. <br />Determine total pipe length. <br />Determine liquid volume of pipe, <br />100 feet. (See page E-18) <br />Multiply length by volume: Drainback quantity <br />_ _ _ _ _ _ feet x _ _ _ _ _ gallons/100 ft ■ _ <br />Suggested drainback quantity is <br />feet. <br />gallons per <br />gallons <br />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.