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�e- <br />F-15 <br />PUMP SELECTION PROCEDURE <br />A. Determine pump capacity: <br />1. Minimum suggested is 600 gallons per hour (10 gpm) - <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 <br />SELECTED PUMP CAPACITY . . . . . . . . . . . . . . . . <br />7S, S gpm <br />B. Determine head requirements: � �nl Find <br />Vim! �-� <br />e �� <br />6p gE <br />I. Elevation difference between Rump and point ofdischarge <br />2. If pumping to a pressure distribution system, add 5 feet <br />for pressure required at manifold . . . . . . . . . . <br />feet <br />3. 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. = 8, $8 ft/100 ft <br />b. Determine total pipe length from pump to discharge <br />point. Acid 25 percent to pipe length for fitting <br />loss, or use a fitting loss chart. Equivalent pipe <br />lcrgch = 1.25 time.,; pipe lenpch = .1.25 x <br />f`et <br />C. Calculate coral friction loss by multiplying; <br />friction 10ti5 in ft/L00 ft by equivalent pine <br />length. <br />Total friction loss = .,58 f` -_ x � <br />feet <br />4. Total head required is the sum of elevation difference, <br />special head requirements, and total friction loss. <br />+ s + /o. 7 <br />TOTAL HEAD . . . . . . . . . . . . . . . . . . . . . . <br />/49. 7 feet <br />C. Pump selection <br />1. A pump must be selected fo deliver at least 7S. S gpm <br />with at least 7f. 7 feet of total head. <br />D. To maximize pump life select sump size for 4 to 5 pump <br />operations per day. <br />V- Calculate drainback <br />1. Determine total pipe length, _ _ feet. <br />2. Determine liquid volume of pipe, / 7, y3 gallons per <br />100 feet. (See page r-18) <br />3. Multiply length by volume: Drainback quantity = <br />f0.0 feet x / 7, 93 gallons/1-00 ft = 17. 32 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 />