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Are either of those pump magnetically driven impellers? Im pretty sure the reeflo is not.
Magnetic pump question-restricting output and electrical consumption?
- Thread starter acroholic
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Are either of those pump magnetically driven impellers? Im pretty sure the reeflo is not.
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You are correct neither are magnetic driven. They are direct driven. Dave and myself are going to test the mag drives. I am going to test a mag 7 mag 9, coralife 1100p and a bluline 200 all of which are magneticly driven. Also the coralife and the bluleline are external mag drive pumps
there's been a LOT of back and forth on this one...
look at it this way (when addressing whether a pump will be damaged by restricting the outflow line)...
when you restrict flow you're essentially ADDING water column head pressure..
the pump is inanimate.. it doesn't know whether the ball valve is only partially open or whether it's got to pump the water up an additional 4' of vertical height..
look at it this way (when addressing whether a pump will be damaged by restricting the outflow line)...
when you restrict flow you're essentially ADDING water column head pressure..
the pump is inanimate.. it doesn't know whether the ball valve is only partially open or whether it's got to pump the water up an additional 4' of vertical height..
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How does this answer the ? of wattage use? Would it recognize it as head pressure or static pressure?
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We can debate what we think or we can base it on actual test.The direct drives will decrease wattage with resistence on the outlet- proven with actual test. I think we will find that all centrifugal style pumps with electrical motors will also.Regardless of the link between the motor and the impellar
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My bad. Is it velocity pressure or static pressure head? The reason I ask, a venturi placed in line will increase water velocity but<u> decrease pressure</u></em> there by creating the suction of air or whatever into the stream. That's my reason in asking because resistence is resistence but where and how it is applied makes a world of difference in hydrodynamics.
As Joe said, I picked up his Kill-A-Watt meter. Thanks Joe. I tested it on the magnetic drive Eheim 1262 submersible pump I have as the circulation pump for my 1/2 horse chiller, and this was tested while doing that. Real world stuff, I guess. I have a ball valve on the output. 3/4" tubing throughout and 3/4" inlet/outlet on the chiller.
Now this pump is supposed to draw 80 watts when on, but when I plugged it into the meter, at full throttle (ball valve completely open) it only drew 50 watts continuous. Not bad. Pretty efficient. Then I closed the ball valve about halfway (90 degree turn from full open to full stop) and the watts used went down to about 43, then to almost closed (10-15 degrees open) the watts used went down to 35.
So I guess the answer is yes to my question. The watts drawn goes down when you restrict the output of a magnetic drive type submersible pump.
BUT, it really didn't go down that much, which makes me think that an oversized pump with the output valved down is not the best choice for any application because the amount of watts used is still going to be higher than a less powerful pump wide open. So if you need, say, 500 GPH you'd be better off getting an Eheim 1260 (600 GPH) and running it wide open instead of a 1262 (900 GPH) and ball valving down the output. If the 1260 is as efficient as the 1262, it will likely draw less watts and pump more than a 1262 valved down to a comparable flow rate, costing less to run and costing less to buy as well.
So I would have to draw the conclusion that the best choice would be a pump appropriately sized to the task at hand, runnign fully open, at least in regards to a mag drive type submersible.
If what I posted is wrong, please feel free to correct me.
I have a Pan World 100-PX-X external I use as a return for my 210 I will test as well and report back.
Dave
Now this pump is supposed to draw 80 watts when on, but when I plugged it into the meter, at full throttle (ball valve completely open) it only drew 50 watts continuous. Not bad. Pretty efficient. Then I closed the ball valve about halfway (90 degree turn from full open to full stop) and the watts used went down to about 43, then to almost closed (10-15 degrees open) the watts used went down to 35.
So I guess the answer is yes to my question. The watts drawn goes down when you restrict the output of a magnetic drive type submersible pump.
BUT, it really didn't go down that much, which makes me think that an oversized pump with the output valved down is not the best choice for any application because the amount of watts used is still going to be higher than a less powerful pump wide open. So if you need, say, 500 GPH you'd be better off getting an Eheim 1260 (600 GPH) and running it wide open instead of a 1262 (900 GPH) and ball valving down the output. If the 1260 is as efficient as the 1262, it will likely draw less watts and pump more than a 1262 valved down to a comparable flow rate, costing less to run and costing less to buy as well.
So I would have to draw the conclusion that the best choice would be a pump appropriately sized to the task at hand, runnign fully open, at least in regards to a mag drive type submersible.
If what I posted is wrong, please feel free to correct me.
I have a Pan World 100-PX-X external I use as a return for my 210 I will test as well and report back.
Dave
I think an open venturi will lessen the draw of a pump. My Orca 200 skimmer recirculation pump is a Dart Gold (I think) rated at 3800 GPH. If I restrict the airflow too much it blows the fuse on the CoralVue float switch in my skimmer waste collector (float controls power to the feed and recirc pump). It makes the amperage draw go up, I guess, 'cause fuses are rated in amps, right?
Anyways, when I restrict the venturi it sounds like the pump is working harder as well.
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It is possible that a draw increase comes about from cavitation on a recirculation pump not sure though. I assume that it is a needle wheel pump? If so I assume the formulas and theoroms change with those type pumps. I would like to learn more about them. I will post some results from my test as well when i complete them. It is interesting the amount of draw down of watts that you experienced. It would be nice to have some formula to use in detewrmining when to buy a larger and throttle back or to do like you said and buy maxed out pump.
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I think we would have to actually measure the flow(gph) at those ball valve position to actually get a gph to watt ratio to determine the efficiency of oversizing or maxing out the pumps. Or maybe you did that and I missed it. Not being argumenative just thinking outloud.
The difference in the 80 watts listed and the 50 watts experienced is probably due to the head pressure the pump is experiencing from pumbing and the chiller barrel. the 80 watts is usually at 0 feet of head.
Dave
I think we would have to actually measure the flow(gph) at those ball valve position to actually get a gph to watt ratio to determine the efficiency of oversizing or maxing out the pumps. Or maybe you did that and I missed it. Not being argumenative just thinking outloud.
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I will be testing some mags 7 and a 9.5
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[
It is based on the Bernoulli equation .
]
It is based on the Bernoulli equation .
I tested my Pan World 100 PX-X (supposed to draw 130 watts). This pump is an external return for my 210. Output is split into two returns. full open it drew 120 watts, and the rating remained unchanged thru the entire range of the ballvalve. Drew the same watts totally closed or open or anywhere inbetween.
Not sure what kind of drive this is, but I believe it is the same type as an Iwaki.
I have a mag 5 and mag 9 sitting on my shelf. I will test these as well with no tubing attached.
Dave
Not sure what kind of drive this is, but I believe it is the same type as an Iwaki.
I have a mag 5 and mag 9 sitting on my shelf. I will test these as well with no tubing attached.
Dave
No I didn't measure flow. Anything I said about efficiency was a complete guess on my part!
But there definitely was resistence thru the chiller/tubing/fitings, so that could be the reason it was only drawing 50 watts when tested. Makes sense since the watts drawn went down even further as I ball valved it down more and more.Dave
Last testing report: What I thought was a Mag 9 is a Mag 12. I filled up a roughneck tote with water and ran the 12 full open with no ballvalve on it. It is supposed to draw 120 watts, and it drew 100. I then put a ballvalve on the output and the watts drawn went down as I closed the valve more and more. The watts drawn went to 36 fully closed. So Mag Drives follow the same pattern as Eheims: ball valve down the output, and the pump draws less wattage.
Dave
Dave
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I went downstairs to start testing and the only meter I have has no amp test. sounds like you covered them all. One question about the pan world is it split after the ball valve?
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Got it. That is interesting. Thanks Dave now I will not get to bed before 4 am until I find out why! lol