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F-15 <br /> PUMP SELECTION PROCEDURE <br /> � <br /> A. Determine pump capacity: <br /> 4; <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 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 /> r <br /> SELECTED PUMP CAPACITY . . • . • • • • • • • • • • • • � `� RPm <br /> B. Determine head requirements: <br /> 1. Elevation difference between pump and point of dischar�e �� feet <br /> •• 2. If pumping to a pressure distribution system, add 5 feet <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 per 100 feet from page F-18. <br /> � � '� F." L. = ft/100 ft <br /> �_ �r`� b. Determine total pipe length from pump to discharge <br /> � point, Add 25 percent to pipe length for fitting <br /> ?� " <br /> ���� � loss, or use a fitting loss chart. Equivalent pipe_ , <br /> �, length = 1.25 times pipe length = 1.25 x ;�=� _ / % `, feet <br /> � ' c. Calculate total friction loss by multiplying <br /> J ,_ ti , friction loss in ft/100 ft by equivalent pipe <br /> .(, length. ! <br /> �'';��� Total friction loss = / � ' x t� : a�� _ � � � feet <br /> �� J 4. Total head. required is the sum of elevation difference, <br /> ���;,!> special head requirements, and total friction loss. <br /> 1_: + + <br /> �s� � <br /> TOTAL HFAD . . . . . . . . . . . . . . . . . . . . . . � � f e e t <br /> C. Pump selection <br /> 1. A pump must be selected to deliver at least ��-� 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 /> E. Calculate drainback <br /> 1. Determine total pipe length, feet. <br /> 2. Determine liquid volume of pipe, gallons per <br /> 100 feet. (See page E-18) � <br /> 3. Multiply length by volume: Drainback quantity = <br /> feet x gallons/100 ft = 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 />