Page 360 of AES Mastercatalog by Aquatic Eco-Systems

pumps tech talks tech talk 61 friction loss in pvc plumbing actual pumping system using the she2.4 pump 4 vertical head 4 the aes technical department set up this actual pumping system shown at right six different times using our she2.4 pump two elbow types and three pipe sizes were used to illustrate the importance of correct plumbing study the results below to understand these principles · elbows vs sweeps · flow vs pipe size · vertical head vs total discharge head · pumping cost vs head note centrifugal pumps not self-priming perform best with flooded suction pumps filled by gravity as shown the suction pipe should be nonrestrictive to control pump s output put a valve on the discharge side pipe size ell style vertical head measured total discharge head ft water gpm pumped 5 elbows or sweeps each test used 40 of piping running amps 115v kw she2.4 pump pumping time per 100,000 gal pumping cost per 100,000 gal 10¢ kwh 11/4 11/4 11/2 11/2 2 2 90° sweep 90° sweep 90° sweep 4 4 4 4 4 4 13 12.8 12 10.4 7.4 6.5 34 37 45 49 57 62 2.2 2.2 2.3 2.3 2.3 2.3 .26 .26 .27 .27 .27 .27 49 hours 45 hours 37 hours 34 hours 29 hours 27 hours 1.27 1.17 1.00 .92 .78 .73 all pvc pipe was schedule 40 elbows were 90° short cost is based on 10¢ per kwh actual vertical head was only 4 feet important vertical head is always measured from water surface as shown not from pump this example is total discharge head only for total dynamic head tdh entrance and friction losses on the pump inlet side must be added feet of head loss per 100 at diameter inches flow gpm .5 1 2 3 4 5 10 15 20 30 40 50 60 70 80 90 100 150 200 1/2 3/4 plastic pipe selection chart .3 1.1 4.1 8.6 14.8 22.2 80.5 1.0 2.2 3.7 5.7 20.4 43.3 73.5 1 .3 .7 1.1 1.7 6.3 13.4 22.8 48.1 82.0 11/4 .3 .5 1.7 3.5 6.0 12.7 21.6 32.6 45.6 11/2 .8 1.6 2.8 6.0 10.2 15.4 21.6 28.7 36.8 45.7 56.6 friction loss in pvc pipe 2 .2 .5 .8 1.9 3.0 4.6 6.4 8.5 10.9 13.6 16.5 35.0 59.4 21/2 .3 .7 1.3 1.9 2.7 3.6 4.6 5.7 6.9 14.7 25.0 1 from the chart at left using gpm and pipe size find the friction loss per 100 of pipe example 40 gpm in a 11/2 pipe 10 loss per 100 of pipe 40 then causes about 4 of head loss 2 next find the friction loss caused by the fittings please note that the friction loss depends on the fitting diameter a standard 1.5 elbow is equal to about 4 of pipe long elbows sweeps and 45° elbows are equal to about 2 of pipe straight through a t about 3 of pipe and a 90° turn through a t about 9 of pipe example 40 gpm through 5 standard 1.5 elbows 20 of pipe which equals 2 of head loss add this to the pipe s head loss and the actual vertical head height in feet to get total dynamic head tdh all pumps sold by aes are performance tested it is up to you to determine which pump to purchase and how to plumb it correctly if you need help send us a sketch and we ll size the pipe for you at no charge note the electric energy required for a centrifugal pump usually goes down as the head pressure goes up it is the opposite of an air compressor tech talk 10 water pump working too hard 3 to trim the impeller remove the pump case volute and carefully trim 1/8 off the impeller diameter in some cases this can be done by very carefully holding a file to the impeller while the pump is on put the pump back together and test the amp draw again repeat the trimming procedure until the desired amp draw is achieved remember that trimming reduces the gpm to be absolutely certain that motors won t fail due to excessive amp draw always check volts and amps at the motor while the pump is running at full load in many places with 110­120v service a voltage variation from 105 to 126 may occur a motor s amp draw will be the highest when the voltage is the lowest so check the full load amps when the facility s voltage is lowest and while all other equipment on that circuit is in use you will only know if your pump is working too hard by measuring the pump motor amp draw at the motor if it is drawing more amps than the full load amps fla rating on the motor label there is a serious risk of burning out the motor to reduce the amp draw do one of three things get full voltage to the motor by using heavier wiring restrict the pump discharge or trim the impeller 1 check the voltage at both the pump and the source if it is less than 5v or more at the pump a heavier gauge wire will reduce the voltage drop and thus the amp draw 2 pump discharge can be restricted by using a valve but there is a risk of someone opening the valve later in place of a valve use a permanent restriction such as a reducer fitting in the discharge pipe order online aquaticeco.com order by phone 877-347-4788 tech support 407-598-1401 357

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