Help selecting new VS pump to replace old Jandy/AO Smith single speed

Summerfell-a

Member
May 25, 2020
7
Carroll County, MD
Pool Size
22500
Surface
Plaster
Chlorine
Liquid Chlorine
My old single speed pump (Jandy MHPU Series, with Century Centurion/AO Smith motor) sounds like it's about to explode and I'm taking this as my cue to upgrade to a new VS pump. I have been doing a lot of reading and research here on TFP as well as other sites to try to fully understand how to select the right VS replacement pump, but I'm just not confident I'm getting it right.

First, I have been unable to find the true "Total Horsepower" of my old pump. It's listed as 2.0 HP "Uprated", but the catalog number and the service factor number on the label are blank. Pics attached.

Then, I tried calculating my pool's TDH, but I'm really questioning the number I got (roughly 25 ft/hd). I don't have piping plans, so I just got out the tape measure and guessed where I thought the pipes were laid. It's a 22,500 gallon in ground pool. It's all 2" piping. I have 3 return lines that each come all the way back to the pool pad. I have 2 skimmers and 1 main drain pipe (with 2 drain openings in the bottom of the pool, but I don't think that matters, right?). The pump pad is about a foot or 2 above the water level and sits roughly 40' away from the center of the deep end. I have a Pentair Quad DE60 filter. You'll see a heater in the pictures below, but it's never worked and I cut it out of the piping a couple years ago (though I haven't ruled out putting in a new heater someday). I currently do not have an SWG installed, but I am putting one in when I do this pump replacement. I already bought a CircuPool RJ45+ (it was on a decent sale last week and I pulled the trigger). I plan to run the new VS pump a good bit of the day at a low speed (maybe 50 gpm?), acknowledging that I might also have to do a cycle at a higher speed to skim. Does that sound right?

I have, perhaps unwisely, limited my VS pump search to Pentair, and more specifically the Intelliflo3 VSF models. This might be a little more sophisticated than I need for my pool...I don't have any water features or spa or anything. But I have been swooned by the concept of being able to use the Pentair Home App to control it. I already use the app to control my Pentair Prowler 930W robot, and I like the idea of being able to introduce a little automation without having to get the Intellicenter or some other full-on automation setup. I was thinking of getting the Intelliflo3 model that has the built-in I/O board and using one of the relays to enable/disable the new SWG, as I've read on here that it is unwise to rely on just the SWG flow switch. It looks like the Pentair Home App lets you program whether each relay is active or inactive during various programs you create; I thought this seemed pretty slick as opposed to installing a separate standalone timer for the SWG.

So if that logic isn't crazy, my biggest question would be, do I need the 1.5HP or the 3HP Pentair Intelliflo3 VSF? But I'm really open to any other suggestions or criticisms as well. I've pretty much completely bogged my brain down to a stand-still with this decision at this point. Just trying to figure out if I've been looking at this correctly and come to a decision before this old pump calls it quits.

The pool guy (who I will always refer to as "Tommy the Pool Man") referred me to TFP eight years ago when I moved into this house and inherited my first pool, and it has helped me look like a pool pro...to the wife and kids anyway...ever since. So I'm hoping you all can help guide me here. Thanks.
 

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Welcome to the forum!
I always recommend getting a full 3 hp VS pump. The de-rated pumps use more electricity and are noiser to move the same amount of water.
Get the Intelliflo3 with I/O board. I would also recommend getting the touchscreen pad so you do not have to rely completely on the app.
I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool
 
Welcome to the forum!
I always recommend getting a full 3 hp VS pump. The de-rated pumps use more electricity and are noiser to move the same amount of water.
Get the Intelliflo3 with I/O board. I would also recommend getting the touchscreen pad so you do not have to rely completely on the app.
I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool
Thank you for the quick reply. I have read a lot of the Pool School material, and actually watched my first TFP video last week...a virtual "expert discussion" about SWCG's which helped me come to the decision to buy one.

As for the pump, does it not matter that the Intelliflo3 VSF max flow rate is 160 GPM (it sounds like technically 140GPM in flow mode) and my Quad DE60 filter max flow rate is 120 GPM? I saw that there was a way to limit the maximum speed/flow of the Intelliflo3 in the programming menus. Would I just need to do that in order to protect the filter during "prime" cycles when the pump runs at full speed? Or is there something else about the piping system that is going to inherently keep the flow under 120GPM?
 
That max flow rate is at run out. Your system will never see that flowrate. Piping, suction, filter, etc induce head losses.
And yes, you can limit to a max rpm (or gpm).
 
That max flow rate is at run out. Your system will never see that flowrate. Piping, suction, filter, etc induce head losses.
And yes, you can limit to a max rpm (or gpm).
I just realized I misspoke about a key detail yesterday (which you can see in the picture). Not sure how I've been thinking about this wrong the whole time...but I do NOT have 3 return lines that go all the way back to the pad. There is only one 2" return that comes out of my filter and goes into the ground. Then somewhere along the way it branches to the 3 return ports in the pool. I do have 3, 2" suction lines that go all the way from the pad to each skimmer and drain.

Does this change your recommendation? Won't I only be able to see a max of 80 or so gpm in the system due to that one 2" return?
 
Will not make a difference. I only have one 2" line to my 2 returns. No issue. I have a full 3.95 hp Intelliflo VS.
 
Will not make a difference. I only have one 2" line to my 2 returns. No issue. I have a full 3.95 hp Intelliflo VS.
Is the allure of the larger pump purely the ability to run the 3HP (or your 3.95HP) at a lower rpm to achieve a desired flow, as opposed to running a 1.5HP pump at a higher rpm to achieve the same flow? Does running the 3HP pump at say 50% speed cost that much less than running the 1.5HP at 65%? The larger motor would at some point consume more energy than the smaller motor right?

I haven't been able to find pump curves for the Intelliflo3's that show the efficiency or "BEP" or energy usage.
 
Running a higher hp pump at a lower rpm to move the same amount of water uses less energy and is quieter.
 
Thanks Marty. So I've decided to get the 3HP, but of course the model with the touchscreen is out of stock, so I have a wait a bit longer for it. In the mean time, I have a couple other questions.
1. Probably a silly question...is it dangerous to continue running my existing pump a couple hours here and there as it grows louder and louder until my new pump comes in? I had it on for a few hours the other night and the noise got really bad (I'm assuming bearings...though I don't really know what that sounds like), and it actually shut off on its own; I'm assuming on some kind of high temp or internal overload (it was really hot to the touch). It didn't trip the breaker and I thought it was done for, but it actually started back up when I flicked the switch for a couple seconds yesterday. Common sense tells me to just never turn this pump on again, put a floating chlorinator in, maybe some algaecide and hope I can hang on without flow until the new pump arrives.
2. I'm trying to figure out where to pipe in my new SWG...since the pool service company installing the pump says they won't touch the chlorinator because I didn't buy it from them. My pad configuration is not very friendly. Is it a bad idea to install the SWG flow switch directly after the cell? The RJ45+ manual says it's okay but leads me to believe this is not preferred...also, it seems to me like being that close to the outlet of the SWG would just shorten the lifespan of the flow switch.
3. I've seen the "Vertical Installation Kits" that the SWG manufacturer's make, which would help me, but the manual also notes very subtly that the cell should be installed a particular way, it shows the cell horizontally turned over and "drooping down" instead of humped up like a camel, if using a VS pump on low speed...which I will be. So I'm thinking a vertical installation would NOT be a great idea for a VS pump on low speed as well; am I right?
4. Is it acceptable, to install the pump up on "blocks" or something in order to give me enough clearance to run the SWG in a sideways U-shaped run (sort of like the vertical install kits do, but on its side) underneath the return line to the pump...sort of over towards where my old heater piping goes (which would also prep me for if I ever install a new heater). Or is it a bad idea to put the pump on anything but solid ground?
Any other recommendations on how to fit the SWG in my setup? The one I bought needs at least a 27" straight span with the flow switch installed upstream, 21" if installed downstream of the cell.
 
I know my posts have been a bit "TL/DR", but does anyone have any advice regarding the SWG orientation, flow switch location, and/or the idea of setting the pump up on some anchored blocks or pavers or something in order to get some more clearance under the incoming pipe? Or I guess for that matter, I could set the filter up on pavers to allow me to pip overtop of the pump suction pipe. Maybe that would be a better idea?
 

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