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F-15 <br /> PUMP SELECTI N PROCEDURE <br /> A. Determine pump capacity: <br /> 1. Minimum suggested is 600 gal ons per hour (10 gpm) <br /> to stay ahead of water use r to <br /> 2. Maximum suggested for delive y to a drop box of a home <br /> system is. 2700 gallons per h ur (45 gpm) to prevent <br /> buildup of pressure in drop ox <br /> 3. Use value from design of pre. sure distribu•t'ion system <br /> SELECTED PUMP CAPACITY. . . . . . . . . . . . . .. . _..__2gpm <br /> B. Determine head requirements: <br /> 1 . Elevation difference between ump and point of discharge 7 t feet" <br /> 2. If pumping to a pressure dist ibution system, add 5 feet <br /> for pressure required at mani old 5 feet <br /> 3. Friction loss <br /> a. Enter friction loss table with gpm and pipe diameter. <br /> Read friction loss in fee per 100 feet' from page F-18. <br /> F. L. _ 9 ft/100 ft <br /> b. Determine total pipe leng h from pump to disclrar•ge <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 /Zp = 150 Moet <br /> C. Calculate total friction 1 ss by multiplying <br /> friction loss in ft/100 ft by equivalent pipe <br /> length. Ii „ <br /> Total . friction loss /pp x /SO = �,3. y _ feet <br /> 4. Total head required is the 'sum of elevation difference, <br /> special head requirements, and total friction loss. <br /> 7 + + s + 3. y <br /> TOTAL HEAD . . . . . . . . . . . . . . . . . . . . <br /> 25 `/ f c:G t <br /> C. Pump selection <br /> 1. A pump must be selected to deli or at least 2 6. 6 gpm <br /> with at least 25. 11 feet o total head. <br /> D. To maximize pump life select sump s ze for 4 to 5 pump <br /> operations per day. <br /> I:. Calculate drainback <br /> 1 . Determine total pipe length, /2 D feet. <br /> 2. Determine liquid volume of. pipe, -7.77 -`gallons per <br /> 100 feet. (See page E-18) <br /> 3. Multiply length by volume: Drainback quantity = <br /> /LD feet x 7.7 7 gallo s/100 ft = 1j, 3 gallons <br /> 4. Suggested drainback quantity is 0 percent. of pumped quantity. <br /> A larger drainback percentage wi 1 decrease pump station <br /> efficiency. slightly but pumping nerfiy costs are usually a <br /> relatively small part of the tot 1 household energy costs. <br />