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�% d fORG o�h S <br />PUM1' SELECTION PROCEDURE <br />A. Determine pump capacity: <br />1. Minimum suggested is 600 gallons per hour (10 gpm) 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 <br />F-15 <br />SELECTED PUMP CAPACITY . . . . . . . . . . . . . . . . S <br />B. Determine head requirements: <br />I. Elevation difference between pump and point of discharge <br />'f_ feet <br />2. If pumping to a pressure distribution system, add 5 feet <br />_,5 <br />for pressure required at manifold . . . . . . . . . <br />S feet <br />3. Friction loss <br />--- — <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. = 7 /Y ft/100 It <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 150 <br />7,S feet <br />c. Calculate total friction loss by multiplying, <br />Friction loss in ft/100 ft by equivalent pine <br />length. <br />Total friction loss = _7, /y r. /. P7.S <br />�/ feet <br />_ __ <br />4. Total head required is the sum of elevation difference, <br />_/�, _ <br />special head requirements, and total friction loss. <br />S f + s + /�. Y <br />TO'rAL IIRAD . . . . <br />7 f/ + <br />. . . . . . . . . . . . . . . . . <br />feet <br />C. Pump selection <br />1. A pump must be selected to deliver at '_east -7S. 5 gpm <br />with at least 2 Y.V ! feet of total head. <br />D. To maximize pump life select sump size for 4 to 5 pump <br />operations per day. <br />E. Calculate drainback <br />I. Determine total pipe length, _ feL-t. <br />2. Determine liquid volume of pipe, p,.:llons per <br />100 feet. (See page E-18) <br />3. Multiply length by volume: Drainback quantity = <br />feet x gallons/100 It = gallons <br />4. Suggested drainback quantity is 10 percent of r -led quantity. <br />A larger drainback percentage will decrease I •:tion <br />efficiency - slightly but pumping energy costs :. '.ly a <br />relatively small part of the total household t. sts. <br />