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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 d home <br /> system is- 2700 gallons per hour (45 Rpm) to prevent <br /> buildup of pressure in drop box <br /> 3. Use value from design of pressure distribution system <br /> SELECTED PUMP CAPACITY <br /> . . . . . . . . . -460. 6 gpm <br /> B. Determine head requirements: <br /> • 1 . Elevation difference between pump and point of discharge. <br /> �• If pumping to a pressure distribution system, add 5 feet feet��•r�- <br /> for pressure required at manifold . . . . . .` feet <br /> 3. Friction loss ------ <br /> a. Enter friction loss table with gpm and pipe diameter. <br /> Read friction loss in feet <br /> per. 100 feet from page F-18. <br /> F. L. _ Y 9 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 15 _ //C; 8 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 = p 9Ai.; x //� �' _ ��, 6 feet <br /> 4. Total head required is the sum of elevation difference, <br /> special head requirements, and toc•al friction loss. <br /> + s + <br /> TOTAL HEAD . . . . . . . . . . . . . . . . . . . . . . ZS. f eo t <br /> . C. Pump selection <br /> 1. A pump must be selected to deliver at least Z e. 6 gpm. . <br /> with at least 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 pipe length, 9.S feet. <br /> 2. Determine liquid volume of pipe. 7.7 7 gallons per <br /> 100 feet. (See •page E-18) <br /> 3. Multiply length by volume: Drainback quantity = <br /> ,- 5?57 _ feet x '7. '7 gallons/100 ft - 7, gallons <br /> 4. Suggested drainbac qac uantity is 10 p`reerlt 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 />