Q on old Jandy single speed pump

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jesse-99

jesse-99

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May 2, 2021
724
Illinois
Pool Size
33000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Jandy Aquapure 1400
So up until this morning, my beach jets/bubblers were powered by a single speed Jandy pump. This whole time, I thought it was a 1HP pump, but I'm beginning to suspect the motor/guts were swapped out ages ago by a 2HP or 2.5HP version reason being (the previous service tech guy used to cannibalize things like that sometimes)... I just replaced that pump with a 3HP Pentair VSP (011056) today, and when the new Pentair 3HP pump is running he 2750 rpm, the beach jets/bubblers have the same flow/height as the old "1 HP" pump. That doesn't seem right to me, which is why I'm thinking the old pump wasn't 1HP, maybe the motor was swapped out to a 2HP or 2.5HP without me even knowing .

If I set the new Pentair 3HP pump to run at 3450rpm, the beach bubblers do go "slightly" higher than the old Jandy "1.0HP" pump, but not by much. I just can't believe a 3HP Pentair pump barely outflows a 1HP -13-year old Jandy pump.

Thoughts? Likely the 1HP pump wasn't a 1HP pump afterall? or am I missing something here (suction side and output side valves are all the same settings).

Thanks.
 
Well hmm, maybe what I thought was a 1.0HP pump is really 1.65HP. I get so confused by how manufacturers label "HP" whether its Jandy, or Pentair with the THP stuff etc.

Pic of the motor area.
8921006262465023757.jpg
 
jesse-99 said:
Well hmm, maybe what I thought was a 1.0HP pump is really 1.65HP. I get so confused by how manufacturers label "HP" whether its Jandy, or Pentair with the THP stuff etc.

Pic of the motor area.
View attachment 513940
Click to expand...
All electric motors have a service factor, as represented in that label. Total horsepower (THP) of the old pump was 1.65. That's the maximum effective work you could expect. Your new pump is 3hp THP at its full speed only. They are called variable-speed pumps, but more correctly they are variable horsepower. At 2750 it is doing the work of the old (or more).
 
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Well take for example my picture attached in the above post. HP is 1. SF is .65 .. what does SF mean/do?
 
1689468006542.png

Your new pump is about 3,200 watts at full speed and full flow.

Your old pump was about 1,650 watts at full speed and full flow.

If the new pump is 3,200 watts at 3,450 RPM, then you can use the pump affinity law to estimate the pump power at any speed.

P1 = P2(N1/N2)^3

P2 = P1/(N1/N2)^3

P2 = 3200/(3450/N2)^3

Y = 3200/(3450/X)^3

The X-axis is the RPM and the Y-axis is the Power in Watts.

1689467959030.png


Y = 3200/(3450/X)^3, X = 0 to 3450 - Wolfram|Alpha

Wolfram|Alpha brings expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels.
www.wolframalpha.com www.wolframalpha.com

To find the RPM that would use the same power as the old pump.

P2 = 3200/(3450/N2)^3

(P1/P2)^(1/3) =N1/N2

N2 = N1/(P1/P2)^(1/3)

N2 = 3450/(3200/1650)^(1/3) =2766.5 RPM.

jesse-99 said:
I just replaced that pump with a 3HP Pentair VSP (011056) today, and when the new Pentair 3HP pump is running he 2750 rpm, the beach jets/bubblers have the same flow/height as the old "1 HP" pump.
Click to expand...
So, this comes out about right.

1689468844143.png
 
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You can look at the power used at different speeds from the pump control panel.

Below is the performance curve for the IntelliFlo VSF (011056) and you can graph the performance curve of the old Jandy 1.65 total HP pump onto this graph to see about what speed the new pump would roughly approximate the new IntelliFlo pump.

What is the model number of the old pump?

For example, if you have a Stealth pump model number SHPF1.0, you can graph the performance curve onto the IntelliFlo performance graph and get the approximate speed that would match the old Jandy pump.


1689471094204.png

full


1689471576850.png

1689471626346.png

 

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What is the model number of the old jandy pump?

The red dots are the SHPF1.0 Performance curve.

If we estimate the flow at 120 GPM at 30 feet of head, then the IntelliFlo speed that would be close would be about 2,730 RPM.

So, the numbers are all pretty close to what you are actually getting.

1689472563031.png
 
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Can you check the Power in Watts, the Flow in GPM and the System Pressure in PSI for these speeds?

RPM...........Watts..........GPM.........System PSI

3,450
3,110
2,750
2,350
1,725
1,500

 
JamesW said:
Can you check the Power in Watts, the Flow in GPM and the System Pressure in PSI for these speeds?

RPM...........Watts..........GPM.........System PSI

3,450
3,110
2,750
2,350
1,725
1,500
Click to expand...
I can try and get that data tomorrow. I think I'll need to disconnect my RS-485 connection first, or I can't really use the panel.
 
As you can see, there is no IntelliFlo Pump Speed Performance Curve that exactly matches the SHPF1.0 Performance curve.

So, to figure out which speed would approximate the performance of the old pump, you would need to graph the pool system curve onto the pump performance curve.

The pool system curve can be different depending on the system configuration.

The speed range is about 2,730 to about 3,150 RPM to match the performance of the old pump.

So, your estimate for the speed vs. the old pump performance is probably pretty accurate.

If you get the data about power, flow and pressure from the pump at different speeds, we can graph the system curve onto the pump curve to see where the operating point is for any speed.

Does the system have the same configuration every time or are there adjustments that you can make?


Pumps_multispeed_0115.jpg



Pumps_Slide2_0115.jpg


1689517795087.png
 
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@James, here you go.
Values taken from the Pentair 011056 control panel as shown. Obviously I can't validate the accuracy of the GPM, etc. but in short, it seems to me that running the 011056 at 2800rpm gives my beach bubblers/jets the same height/flow as did the old Jandy pump, FWIW. (The Pentair seems to use around 1290W at 2800rpm to get the same height/flow as the Jandy did around 1840W at Full rpm).

RPMWattsGPMSystem PSI
3,45024209132
3,11018138326
2,75012777420
2,3508166314
1,725334457
1,500230415

EDIT: "Does the system have the same configuration every time or are there adjustments that you can make?" --- I basically just run it on a schedule at the same RPM every time (I rarely ever change the RPM once dialed in).
 
They go to my 2 beach jets/bubblers, both exits/returns in the beach are always under about 3-4" of water constantly. They shoot up about 12 " above the water level at 2500rpm'ish, so roughly 16" total if you include what's underwater.

1689532787186.png
 
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The blue line is for the old pump, so this is about close to 2,800 RPM to maybe 3,000 RPM to match the old pump.

The flow would be about 80 to 90 GPM, which seems high for the bubblers.

The system also seems more restrictive than I would suspect.

A properly sized water feature should have very low total head loss.

Maybe the plumbing is undersized?

For 90 GPM, the suction should be a minimum of 2.5" and the returns should also be a minimum of 2.5"

As long as you keep the water velocity below 6 ft/sec on the suction and below 8 ft/sec on the pressure side of the pump, you should be fine.

Size.......6 ft/sec......8 ft/sec.

1.5"...........38...............51 gpm

2"..............63...............84 gpm

2.5............90.............119 gpm

3.0".........138.............184 gpm


1689533806353.png
 
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If we assume 100 feet of pipe on the suction and 100 feet of pipe for the return at a flow of 90 GPM, that is a velocity of 6.2 feet per second and 5.2 feet of head loss on the suction and 5.2 feet of head loss on the return for a total of 10.4 feet of head loss.

Your head loss is about 55 to 60 feet at about 80 to 90 GPM, so way more that it should be.

1689535089772.png
 

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