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,BF�Radms SRF-o -7 901e- <br /> PUMP S177LECTION PROCEDURE <br /> A. Determine pump capacity: <br /> 1 . Minimum suggested is 600 gallons per hour (1.0 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' <br /> buildup of pressure in drop box <br /> 3. Use value from design of pressure distribution system <br /> SELECTED PUMP CAPACITY . . <br /> _��.7 Q gp n, <br /> B. Determine head requirements: <br /> 1 . Elevation difference between pump and •Iioii f' of dis�1. 1Tge i <br /> _ .� �_ feet <br /> 2. If pumping to a pressure distribution system, add 5 feet <br /> for pressure required at manifold <br /> 3. Friction loss ____tefeet <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. _ , 6 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 lenp.th = <br /> C. Calculate total friction loss by mul.ti.plyng'iz _ -'"-- <br /> friction loss in ft/:100 ft by equivalent pine <br /> ,.-. <br /> length. 2.6'5/ <br /> Total friction loss = DO x y. /_ _ feet <br /> 4. Total head required is the sum of elevation difference, <br /> special head requirements, and total fricl-icyit .loss: <br /> + —y <br /> TOTAL xFAD . . . . . . . . . . . . . . . . <br /> C. Pump selection <br /> 1. A pump must be selected to deliver at least .. 49*7, Q gpm <br /> with at least /J?. / feet of total head. <br /> D. To maximize pump life select sump size for 4 to 5 pump <br /> operations per day. <br /> X. Calculate drainback <br /> 1 ; Determine total. pipe longth, 2 <br /> --�--- - <br /> • Determine liquid volume of pipe, _ 7, fent ._ gallons per <br /> 100 feet. (See page E-18) <br /> 3. Multiply length by volume: Drainback quantity = <br /> /ZS feet x —017 !�j gallons/100ft - 2/ JO 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 ate usually a <br /> relatively small part of the total household erie'r'f~y <br />