VS or 2 speed pump

Jump to latest Follow Reply
B

Buck Russell

Active member
Mar 26, 2019
27
TN
Trying to make sense of my new to me pool pump requirements.

Currently using a noisy, tired sounding 1.5hp Superpump. Wanting to replace with new VS or 2 speed pump.

Confused about how much flow I need to run a 25k pool with waterfall. Is there a certain flow rate/ hp requirement to actually make the waterfall work? Meaning if I get a VS pump, and turn it down, will there be a certain speed level that won’t push enough water for waterfall?

I don’t want to purchase a new pump and not be able to use a low rpm or lower speed on 2 stage pump.

Using robot for cleaning, so do not need the flow for pressure cleaner.
 
All depends on how waterfall is plumbed. And also how much you want to run it. They raise PH so limited use is recommended. If you can valve off the returns you can run low speed on anything and be able to run waterfall. VS is ultimate control do you have any automation now or a SWG? How do u sanitize pool now?
 
Not sure of the underground plumbing. I have 2 return lines at the pad servicing 2 returns and a pressure port in the pool, and the waterfall. The waterfall has a valve at the waterfall I could use if needed.

I have a SWG now that isn’t working that will be replaced with new pump. Also redoing pad plumbing to remove booster pump and chlorinator.

I have no automation at this time and really do not see the need for my situation. Unless there’s some no brainer must have stuff I need to incorporate in the replumbing/ rewiring I am also doing.
 
Last edited:
Buck,

Take a look at the discharge pressure when your waterfall is running. This is the head required to overcome the head loss of elevation changes and other losses in your system. Then look at the performance curve or performance tables for both pumps. This will give you flow rates that will be achieved by both pumps. On my system the low speed runs the spillover fine just at the lower rate shown on the low speed curve. But it doesn't put out sufficient head to overcome the elevation for the roof mounted solar heater. The VS pump is just like a 2-speed pump curve but it has many more speeds. It's also more efficient because it has a permanent magnet motor which adds significantly to the savings.

Chris
 
Discharge pressure? As in filter pressure? Gauge is normally about 15psi if that is what you are referring to.

If there’s charts and equations I need to consult, I’m going to need some help and instruction.

I’m perfectly fine with the spillover working at a slower rate. I would assume I would never run a VS pump any lower than the SWG requires. If that speed is enough for the waterfall that would be ok.
 
Buck,

Sorry, yes the gauge at the top of your filter is close enough to the discharge pressure. I'll do some calcs and respond in a few. I'm not a pump expert but I can get close, I'll ping one of our experts also. Hopefully they can provide you more detail also. @mas985

Chris
 
The minimum I run my VS pump at is 1500rpms in order to make the SWG happy. At 1500 RPMs I can get some flow on my waterfall. I also have a sheer descent. That requires a LOT more flow than the waterfall. To get decent flow I need to direct almost all the return water to the sheer and put the pump at around 3000 rpms. If you had automation, you could simply press a button and make everything go where it needs to make your waterfall work including pump at the proper speed.
 
I hope I’m describing what I have correctly. Before we purchased home, a pool guy looked at the feature and laughed at the way it was built. Describing it as a glorified bird bath. We like it ok, although it would be fine if it actually slowed down a little.

I would like to do some automation, but I’m afraid when built, there wasn’t much room to add on. Pool roughly 20yrs old.
 

Attachments

  • B6F661C8-C749-4E1C-BD09-25844F2261CF.jpeg
    B6F661C8-C749-4E1C-BD09-25844F2261CF.jpeg
    465 KB · Views: 39
  • 1C67D333-8B48-4EFE-B059-8C38C42553B4.jpeg
    1C67D333-8B48-4EFE-B059-8C38C42553B4.jpeg
    599 KB · Views: 39
Once determined what type/size, I would like recommendations like yours Marty.

This being new to me, pool equipment seems like a Ford, Chevy, Dodge situation.

I wish Toyota made pool equipment, my choice would be easy.
 

Enjoying this content?

Support TFP with a donation.

Give Support
Buck Russell said:
Describing it as a glorified bird bath. We like it ok, although it would be fine if it actually slowed down a little.
Click to expand...

I think you can turn it down or shut it off entirely by turning that red knob in the middle.

I would shut it off and make it into a planter.
 
ajw22 said:
I think you can turn it down or shut it off entirely by turning that red knob in the middle.

I would shut it off and make it into a planter.
Click to expand...

Believe me, I’ve pitched the idea to my wife. Swing and a mis.

She’s wanting to set some planters down into the thing, which should look nice.

Is the actual waterfall a problem or liability to my system? It’s there already and like I said earlier, if the flow was less it would be even nicer.

I don’t know the full scope of it raising the PH since we haven’t had it through the summer yet.
 
The waterfall at a low flow should not be a problem for your pump. It is just another return. Use the red valve to adjust the flow.

You have to see how the aeration affects your pH. Depends on your TA, fillwater pH & TA, and local environment.
 
Buck Russell said:
Confused about how much flow I need to run a 25k pool with waterfall. Is there a certain flow rate/ hp requirement to actually make the waterfall work? Meaning if I get a VS pump, and turn it down, will there be a certain speed level that won’t push enough water for waterfall?
Click to expand...
If by waterfall you mean an elevated rock waterfall (not a spa spillover) then yes. It is more about pressure than flow rate. Assuming a typical rock waterfall, the pump has to lift the water about 6'. This is a constant static head and will limit the minimum RPM to get sufficient flow rate.
 
mas985 said:
If by waterfall you mean an elevated rock waterfall (not a spa spillover) then yes. It is more about pressure than flow rate. Assuming a typical rock waterfall, the pump has to lift the water about 6'. This is a constant static head and will limit the minimum RPM to get sufficient flow rate.
Click to expand...

I posted a pic above. I’m guessing the head of waterfall pipe is approximately 30 inches above the waterline. How far it goes into to ground I do not know.

Is there a simple equation that would tell us the minimum flow that would produce the minimum pressure to operate waterfall?

I do know a 1.5hp Superpump operates it with plenty of water flow. So obviously plenty of pressure as well.
 
Sorry, I missed the picture. 30" will still affect the flow just nearly as much as 6' would.

Each pump will have it's own characteristics specific to your plumbing setup. However, if I make some rough assumptions about your setup and target a flow rate of 25 GPM, the floor for most SWGs, I come up with an RPM of around 1400 (~180 watts) for the SuperFlo VS. Some SWGs operate down to 15 GPM which would take around 1000 RPM. So I think it should be fine even if you went with a smaller VS.
 
I just bought anew Variable speed pump from inyo..My single speed was flowing too much water with all in and outs open and when I tried to isolate the spa it was a challange. Plus it looks like you can set several speeds in a VS and so to them quickly..I am completely re-plumbing everything with the new pump and should know how it works next week :)
 
So consensus is a VS pump will work. Possibility of lower flow on waterfall at lower rpms, which is acceptable to us.

What sizes do I need to be concentrating on? Again, I know the current 1.5hp super pump is more than enough.

Do I purchase a 1.5 and know it will be fine at occasional peak rpms?
Or do I purchase larger pump and let it work easier knowing I’ll never need the higher rpms?

I see water head loss and such figures being used in most calculations. I have no idea on my pool due to not seeing install. I can make a rough guess on feet, turns, and connections, but it would only be a guess.
 
Buck,

Sorry for the delay. I do notice you have the same wife issue I have. My wife loves the spillover... I cut it back to a couple of hours and she wasn't happy. I go by the "happy wife happy life" philosophy so it runs a lot and I just use extra MA. Well worth it!

So back to your pump issue. I got the curves for the Super Pump. Look at the black dotted line for SP2610X15. Y axis is your discharge pressure in ft of head. 15 psi is about 34.6 ft of head. So your flow rate at this condition is about 70 gpm. If you use the 2 speed equivalent you can't get enough pressure to flow anywhere near this amount. Maximum discharge pressure would be 17 ft of head. 6 of this would be required just to overcome the elevation could be more if your fountain is over 6' high. The rest of the pressure drop would be to overcome pressure drop in pipe, valves, fittings, and filter. My rough estimate would be 10 gpm. The actual flow depends on the elevation difference and a little more detail on the piping.

So next we'll go to the VS pump. I used the Hayward Ecostar curve below. Notice here that you'll be able to get about the same performance as you currently do at only 2400 rpm. You should be able to drop well below this and still get sufficient flow for your water feature.

So what does all this mean? The flow rate you are seeing over your fountain currently is about 70 gpm. This is a reference point to compare other lower flow rates. Depending on the elevation from your pump to the top of the fountain, low speed flow rate could be very low (my guess is 10 gpm or less). Another point of reference would be to hook a standard 1/2" hose up and point at the top of the fountain a 25' hose will normally flow at about 20 gpm. Is this enough flow or do you really need more? A VS pump would be a great choice since you have much more flexibility to select the lower speed that still gives you enough flow over the fountain. I really like Marty's suggestion to connect a VS motor drive to your existing pump. This could get you most of the benefit and at a much lower cost than purchasing a new pump and motor. I have no idea how the VS motor on your old pump would perform but I'm sure the supplier can tell you this. You should also do this to price a total new VS unit. Pentair Intelliflow VS pumps seem to have a strong following on here. I would check with them as well. The final decision will come down to economics and your personal preferences. If you plan to add automation later on this could have a big impact since you'll have much more control with your remote or wifi app albeit with more limited brands of pumps. Also consider carefully the warranty issues if you're doing a DIY. With a VS pump and/or motor you definitely want the max warranty you can get.

I hope this helps and one caveat. I've done a lot of work with pumps in industry but I'm not a pool pump expert. Definitely get an estimate of pump and/or motor performance from the supplier. They have techs that are experts on their equipment and their performance estimates are usually very, very close.

Chris




97388

97389
 
Hard for me to believe the flow over that waterfall as shown is 70GPM.

If you go above a 1.5 hp VS motor that I referenced, you would need to rebuild the wet end too.
 

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply