Best return pump

mcarroll

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I say there's no such thing as a free lunch, but you guys have me curious again! :)

I calculated 15.6 feet of head pressure. 10 vertical feet and 14 horizontal feet.
http://www.freecalc.com/fricfram.htm
  • Liquid Friction Pressure Loss
    • Pressure Loss (psi): 6.11 Head Loss (ft): 13.8
    • Line Number:
    • Date: 7/18/2016
    • Nominal Pipe Size: 0.75
    • Pipe Schedule: SCH 40
    • Flow Rate (gpm): 22
    • Viscosity (cP): 1
    • Specific Gravity (water=1): 1.025
    • Temperature (F): 83
    • Pipe Roughness (ft): 0.000016
    • Actual Pipe ID (in.): 0.824
    • Fluid Velocity (ft/sec): 13.24
    • Reynolds Number: 86549
    • Flow Region: Turbulent
    • Friction Factor: 0.02
    • Overall K: 5.06
    • Piping Length (ft): 10
    • Long Radius Elbows: 2
    • Pipe Entrance: 1
    • Pipe Exit : 1

There are lots of variables that measuring would account for, but while we're estimating I just thought I'd add this data point....not far off of what you calculated.

FWIW, from playing with the calculator at rc, the horizontal run seems like it is more or less inert compared to the effect of bends and vertical runs.

To keep it simple, I'm assuming 10' of head loss for the rest of this doc....


DC doesn't save power? Sure does. Here is my comparison. I ran an Iwaki MD-70, 1536 GPH, 336 watts. I'm now running 2 Vectra M1's, 2000 GPH each, 80 watts each. Seems I get more GPH for a LOT less watts. I am saving power over the AC Iwaki I was running.

It seems like you're comparing the nominal ratings of these pumps. The curves are quite different between the pumps mentioned, so this is not an apples-to-apples comparison.

Have you measured the flow rate you're actually getting? (Either before switching to the Vectras or after switching?)

This is the only sure way to know – and easy to accomplish. @SteadyC can you do this?

to test this idea:
i found an amp master 3900.

At 10' up...

It seems like either the high-head Dolphin 6250 or medium-head 4750 would be a better comparisons...but the 4750 will do for us.

Iwaki
$387

1380 GPH is about what I calculate he'd be getting with the old Iwaki. There's no cross reference for power usage at that flow rate.
pu_iwaki_curve.jpg



Dolphin
$450 on Amazon.

1380 GPH from the Amp Master comes in at around 125 watts and up to 11'.

10' will yield more like 1500 GPH at 130 watts.
d996ed_4a75e9fdbe3f4be99514a49aa2408de0.jpg



Vectra
$350 x 2 = $700

1380 GPH from the M1 can be delivered up to 6'...presumably at 80 watts.

Interestingly, at 10' it will push almost 900 GPH

I'm guessing, but I assume the duo of Vectras runs at 160 watts to push up to the second floor? @SteadyC can you take a KillAWatt reading by any chance?

Screen-Shot-2016-04-16-at-12.19.03-PM.png


My Bet
Once actual flow and power usage are measured – I bet it's close to a wash.
 

TaylorPilot

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I say there's no such thing as a free lunch, but you guys have me curious again! :)


http://www.freecalc.com/fricfram.htm
  • Liquid Friction Pressure Loss
    • Pressure Loss (psi): 6.11 Head Loss (ft): 13.8
    • Line Number:
    • Date: 7/18/2016
    • Nominal Pipe Size: 0.75
    • Pipe Schedule: SCH 40
    • Flow Rate (gpm): 22
    • Viscosity (cP): 1
    • Specific Gravity (water=1): 1.025
    • Temperature (F): 83
    • Pipe Roughness (ft): 0.000016
    • Actual Pipe ID (in.): 0.824
    • Fluid Velocity (ft/sec): 13.24
    • Reynolds Number: 86549
    • Flow Region: Turbulent
    • Friction Factor: 0.02
    • Overall K: 5.06
    • Piping Length (ft): 10
    • Long Radius Elbows: 2
    • Pipe Entrance: 1
    • Pipe Exit : 1

There are lots of variables that measuring would account for, but while we're estimating I just thought I'd add this data point....not far off of what you calculated.

FWIW, from playing with the calculator at rc, the horizontal run seems like it is more or less inert compared to the effect of bends and vertical runs.

To keep it simple, I'm assuming 10' of head loss for the rest of this doc....




It seems like you're comparing the nominal ratings of these pumps. The curves are quite different between the pumps mentioned, so this is not an apples-to-apples comparison.

Have you measured the flow rate you're actually getting? (Either before switching to the Vectras or after switching?)

This is the only sure way to know – and easy to accomplish. @SteadyC can you do this?



At 10' up...

It seems like either the high-head Dolphin 6250 or medium-head 4750 would be a better comparisons...but the 4750 will do for us.

Iwaki
$387

1380 GPH is about what I calculate he'd be getting with the old Iwaki. There's no cross reference for power usage at that flow rate.
pu_iwaki_curve.jpg



Dolphin
$450 on Amazon.

1380 GPH from the Amp Master comes in at around 125 watts and up to 11'.

10' will yield more like 1500 GPH at 130 watts.
d996ed_4a75e9fdbe3f4be99514a49aa2408de0.jpg



Vectra
$350 x 2 = $700

1380 GPH from the M1 can be delivered up to 6'...presumably at 80 watts.

Interestingly, at 10' it will push almost 900 GPH

I'm guessing, but I assume the duo of Vectras runs at 160 watts to push up to the second floor? @SteadyC can you take a KillAWatt reading by any chance?

Screen-Shot-2016-04-16-at-12.19.03-PM.png


My Bet
Once actual flow and power usage are measured – I bet it's close to a wash.

No doubt. My thought has always been the best pump depends on your specific application. All of these pump motors are usually within 5-10% efficiency, so it comes down to the design and application of the volute/impeller. If you are low head pressure or a closed loop, then a DC pump would be great. Although when I say DC it really doesn't have anything to do with the pump being DC, it has to do with the trend of most of the DC pumps being built for high flow, low pressure applications. I think allot of it has to do is them wanting to be able to splash a super high GPH/watt ratio on the box, but it is almost always at 0 head. Kind of a useless number honestly. There should be an industry standard 6' and 10' head flow/wattage calculation on their pumps. That would give better real world usage numbers.
 

foxt

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lol. my 6,250 gph pump pulls less than 2 amps.

I am considering a 6250. From the spec sheet, looks like the pump draws a min of 480watts, which would be more lik 2 amps at 120v. How are you pulling less than 2 amps? What kind of head do you have?
 

Russ265

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I am considering a 6250. From the spec sheet, looks like the pump draws a min of 480watts, which would be more lik 2 amps at 120v. How are you pulling less than 2 amps? What kind of head do you have?

ball valve my friend. ball valve. if you dial it back, itll drop the draw.
 

foxt

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ball valve my friend. ball valve. if you dial it back, itll drop the draw.
Can you tell me ifi dial a 6250 back, can i get the same flow per watt that a barracuda would give me at 15' of head?
 

foxt

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Thanks for the chart. I am familiar with it. According to that chart, the pump should never be able to run at 2A / 120V (240W). That is why I was asking Russ265 what head he has on the pump.

According to the chart, if I run 15' of head, the pump will produce 3600gph. I only need about 2000gph, so I can dial it back. I am trying to figure out what kind of power usage I will see if I do so. The barracuda will give me about 2000gph at 15' of head for 237W. Will the Dolphin 6250 give me the same performance? Russ said his pump runs 2A (which is about the same power consumed by the Barracuda). If it can push 2000gph at 15' of head for 240W, I would prefer it over the Barracuda.
 

mcarroll

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I see what you mean now! :)

The 6250 is a 400-500 watt pump - much larger than the Barracuda. I ran a 1000 gallon retail system with one and it was still overkill. :)

I don't think it's going to drop 50% of its power usage just because you apply a ball valve, but I'm interested to hear if that's been people's experience! (Or what their experience has been.)

Anyone? Russ or otherwise, have a killawatt meter?

Seems like there are a lot of people in your situation with a basement sump and around 15' of head....would be interesting to call Dolphin and see what they'd suggest, since your use case falls between their mid-range and high-end pump choices. Their pumps are sweet tho.
 

foxt

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Their pumps are sweet tho.

I'd rather have a Dolphin - I know I can replace the seals on the Barracuda, but it is a hassle, and the Dolphins are said to run quieter. Russ did say that he was running his 6250 at 2A, but I wonder what his flow/head is.

I will try asking Dolphin to see what they say ...
 

mcarroll

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Let us know! I'm wondering if they just expect everyone to use the 6250, or if they'd have a different option of some sort....a custom option or a pump from another line maybe. Or if the ball valve really actually works a small miracle! ;)
 

foxt

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Well, I received an email back from Dolphin, and apparently they recommend the Reeflo. I quote:

"Do you really think a slight savings in watt draw would surpass the cost of bearings, seals, warranty and life of Dolphin VS reeflow, then by all means buy reeflow. We would rather have customers that have to think twice go with reeflow."

Interesting that they don't bother to spell the competitor's name correctly. That aside, I have been doing some figuring with just the published specs. My target flow is 2000gph at 15' head. At 15' head, the Dolphin will draw 485W and flow 3300gph (probably different than real world, but it is all I have). The Barracuda will flow about 2000gph at 237W. That is a difference of 250W, which is 6kwh/day. That is not a "slight savings in watt draw", as stated by Dolphin. At my utility rate, that works out to about $300/yr. If all of this is even close to real-world, I could buy a brand new Hammerhead/Barracuda Gold setup every 1.5 yrs and still break even vs. the 6250. And I won't need a new one that often, but could buy two so that I can swap out the spare and replace the seal when needed.

The engineer in me says that this is just plain wrong on many levels, but barring any other data, it is what it is. I responded to Dolphin asking for clarification, and am hoping that they come back with a better response this time ....
 

mcarroll

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It sounds like some additional diplomacy could have helped in the asking of the question, maybe? ;)

I like their hardware and warranty - they just seem to need a pump in between the 6000- and 4000-series to fit this bill. The 3000 and 4000 don't have the lift and the 6000 is overkill by about double.

(I give anyone leeway to misspell the name of any company who picks a fake word as their name tho! :D)
 

foxt

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The response from Dolphin struck me as dismissive and unprofessional. I didn't insult them with my question, and I shouldn't need to tread carefully when asking a question about competitive position of their product. They claim to be the most power efficient solution, and in this case they don't seem to be, and I was asking them to set me straight about it. And the fact that they chose to be flip about it sorta implies what you are suggesting (at least to me) - they don't have a better answer, and they don't want my business in this particular situation. Funny thing about dealing with these types of questions though, next time I need a pump where they might better meet requirements, I'll recall how they behaved this time.

I followed up by repeating my request for some data about what the expected power consumption might be when restricting the output to 2000gph at 15' of head, and hopefully I get a response. We'll see.
 

foxt

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I am not bashing Dolphin, but this struck me as counter to my experience with them so far ... From the homepage of their website:

"At Dolphin we are dedicated to educating our customers in all aspects of pump purchase, usage and maintenance. If there is something we are missing on our site, please Let us know!"

I had a serious question seeking education on pump purchase, and they basically blew me off. Maybe the guy was having a bad day, so I am giving him a second chance ...
 

TaylorPilot

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I followed up by repeating my request for some data about what the expected power consumption might be when restricting the output to 2000gph at 15' of head, and hopefully I get a response. We'll see.

The chart says that at 33 GPM (2000 GPH), the pump will consume about 450 watts. That is about 19.5' of head pressure. It just looks like the pump is too big for your situation.
 

TaylorPilot

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Head pressure is a little confusing. What it really means is that the back pressure on the outlet of the pump is equivalent to a certain number of feet of water column pressure. So 33 vertical feet of salt water exerts 1 atmosphere of pressure (14.7 PSI). So if you divide that out, each foot of head pressure is actually 0.445 PSI. So when you look at a chart all it is really showing is performance and power draws at a certain amount of back pressure on the outlet of the pump. Whether it is created from actual water column height, or from a ball valve being restricted down, the pump doesn't know the difference. So if you know what GPH you want, you just look at where that number crosses and read out the wattage draw. So with this pump, it is creating 2000 GPH at about 8.686 PSI, also known as 19.5' of head pressure, while drawing about 450 watts or 3.75 amps @ 120V.
 

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