Our new a WhisperFlo is running RPMs at 3450, 3000, 2200 and 1400 that the new FlowRead is showing about flow at 70, 60, 44 and about 18 GPM. There a guy of Swimming Pool Steve who has runs the Pentair pumps many times at the 3450, 3000, 2000 and 1000 RPM and it shows that the meter flows rate at the GPMs show about 102, 86, 55 and 29 GPMs. Why can the meter flows can so different RPMs when so slow the GPMs? Thanks.
WhisperFLo Looking At RPMs
- Thread starter DBissett
- Start date
- Jul 21, 2013
- 65,118
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
D,
Why do you care what the flow rate is?? What problems are you having due to "poor flow"..
Just curious... I have no idea what my flow rate is, and my pool runs just fine..
The whole point of having a VS pump is to run as slow as you can and still get the job done.. I can't think of any reason that I would ever run at 3450 rpm.
Obviously, you can run your pool anyway you want, just curious what your goal is..
Thanks,
Jim R.
Why do you care what the flow rate is?? What problems are you having due to "poor flow"..
Just curious... I have no idea what my flow rate is, and my pool runs just fine..
The whole point of having a VS pump is to run as slow as you can and still get the job done.. I can't think of any reason that I would ever run at 3450 rpm.
Obviously, you can run your pool anyway you want, just curious what your goal is..
Thanks,
Jim R.
"Your pool plumbing has more "head" and is more restrictive and thus less flow." Is this something to increase the flow rate?
- Jul 21, 2013
- 65,118
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Why do you think you need more flow rate?
What are the flow requirements of your pool equipment?
What equipment has flow switches or water pressure switches?
What speeds does your SWG show good flow or NO FLOW?
- May 3, 2007
- 18,071
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
A pump's performance on a particular plumbing system is determine by the operating point which is a crossover of the pump's head curve and the plumbing head curve. The pump's head curve is different for every pump and the plumbing's head curve is different for every pool so you really can't compare the two unless both are identical.
Below is an example of the Whisperflo VS Head Curve with 5 different plumbing head curves. As you can see, the plumbing curves on the left have much lower flow rates and higher head loss than the curves on the right. Your plumbing curve is pretty close to Curve-A which is typical of 1.5" plumbing.
Pump Plumbing Head Curves and Operating Points - Further Reading
www.troublefreepool.com
I just start the reply for your and reading. Thanks to learn.A pump's performance on a particular plumbing system is determine by the operating point which is a crossover of the pump's head curve and the plumbing head curve. The pump's head curve is different for every pump and the plumbing's head curve is different for every pool so you really can't compare the two unless both are identical.
Below is an example of the Whisperflo VS Head Curve with 5 different plumbing head curves. As you can see, the plumbing curves on the left have much lower flow rates and higher head loss than the curves on the right. Your plumbing curve is pretty close to Curve-A which is typical of 1.5" plumbing.
Pump Plumbing Head Curves and Operating Points - Further Reading
View attachment 639141
I've still working out the Pentair WhisperFlo speed changes that it requires for our flow rate. Current the pump 3000 RPM, the Blue-White FlowRead current = 60 GPM, 2200 ROM at 44 GPM, and 1400 RPM at 18 GPM. So our pool has 24000 gal/day. (Have the 24000 is up to more 72000 for some might says so). We have no heat or spa, but has the Pentair DE 60 sqft filter. Our use the SWG has the CircuPool RJ60+. Lets say if 3000 RPM would run 3600/gal will each 24000 almost 7 gal. Is that enough pool, or more, and the SWG runs the chlorine? Resent I've been using about 60% for the SWG chlorine, but it's the 1400 RPM at 18 GPM looks its almost new water is moving when the SWG. (If the 3000 RPM asked if 72000 gal/24 first needed to a 60 GPM needing 3600 gal/24hr needed 20 hrs went is huge number. ) Thanks.
- Jul 21, 2013
- 65,118
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Sounds like you are trying to figure out turnovers which are meaningless…
Turnover of Pool Water - Further Reading
www.troublefreepool.com
Furgetaboutit!
You are making things way too complicated.
D,
A specific Flow itself is not important, the results are what is important..
The main thing that you need to know is what RPM turns your SWCG on.. It does not matter if that is 15 GPM or 20 GPM or 25 GPM.. Flow through the cell has nothing to do with how much chlorine the cell is making.. Turn your rpms down until the SWCG reports low flow.. Then slowly turn the rpms up until the cell reports good flow.. Add 100 rpms and that is the slowest speed your ever want to run..
You should run your pump for a reason, not just to meet some mythical GPM turnover number...
The slower you can run the pump, and still generate chlorine, the better.. It costs less, and is quieter.
Thanks,
Jim R.
A specific Flow itself is not important, the results are what is important..
The main thing that you need to know is what RPM turns your SWCG on.. It does not matter if that is 15 GPM or 20 GPM or 25 GPM.. Flow through the cell has nothing to do with how much chlorine the cell is making.. Turn your rpms down until the SWCG reports low flow.. Then slowly turn the rpms up until the cell reports good flow.. Add 100 rpms and that is the slowest speed your ever want to run..
You should run your pump for a reason, not just to meet some mythical GPM turnover number...
The slower you can run the pump, and still generate chlorine, the better.. It costs less, and is quieter.
Thanks,
Jim R.
Post the filter pressure and flow for different speeds.
What is the exact model number for the pump?
Can you show the system?
What is the exact model number for the pump?
Can you show the system?
Interesting. In your case it means running at 1400 is barely more efficient (gpm/watt) than running at 2200. It doesn't support what I always read : "the slower the better".
- May 3, 2007
- 18,071
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Why do you say that? For the OPs plumbing setup power at 2200 RPM (44 GPM) should be about 475 watts (EF=5.6) while power at 1400 RPM (18 GPM) should be about 131 watts (EF=8.2) so significantly better.
I assumed 560W at 2200rpm and 200W at 1400rpm but your data seems to be more reliable. Do you count the power consumption of the drive itself as well ? As far as I know Pentair doesn't, which underestimates the watts displayed especially at low speeds. It would be interesting if the OP could report back the real numbers.
Anyway we can see that the drop in GPM from 3000 to 2200rpm is linear while the drop from 2200 to 1400rpm isn't. So even if I'm wrong at 1400rpm, I'm pretty sure the efficiency would start decreasing not far from there.
Anyway we can see that the drop in GPM from 3000 to 2200rpm is linear while the drop from 2200 to 1400rpm isn't. So even if I'm wrong at 1400rpm, I'm pretty sure the efficiency would start decreasing not far from there.
Last edited:
- May 3, 2007
- 18,071
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Yes, the drive electronics are included. The data I am using is from Energy Star measurements:
Product Finder — ENERGY STAR Certified Pool Pumps
Compare ENERGY STAR Certified Pool Pumps, find rebates, and learn more.
Where did you get your data from?
I believe that all pump manufactures including Pentair include the drive electronics power in the power display of the pump.
The affinity laws dictate the relationship between RPM, GPM, Head and Hydraulic Power:
Power consumption is related to the Hydraulic HP plus the efficiency of the pump and motor which change with RPM as well and is generally an offset cubic vs RPM where the y-intercept (i.e. RPM=0) is basically the drive electronics. In most cases, RPM below 1000 does not make a lot of sense as the wattage does not decrease much but the GPM still does. Plus, when the flow rate gets too low, then the skimmers, SWGs, heaters, etc. fail to work properly.
Here is the power curve for the Whisperflo on Curve-A (OPs plumbing curve):
But for the Whisperflo, the EF increases down to about 500 RPM which is lower than some other pumps:
Last edited:
- May 3, 2007
- 18,071
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
The thing is that the curve A does not represent OP situation, so anything deriving from it is going to be potentially false. The curve is a perfect match at 3450, 3000, 2200rpm but way off at 1400 : ~28gpm predicted vs 18 reported. Something is missing (static head maybe ?). Seeing how the flow rate seems to plummet already at 1400rpm, I really doubt the OP would reach the maximum efficiency at 500rpm (I'd bet he'd have barely any flow at that speed).
Thanks !
The smart meter of my utility company is reporting ~40W more than what the pentair drive is showing at any speed. I'm pretty sure I read someone else reporting the same. But I'll check again next time.
Thanks !
Last edited:
- May 3, 2007
- 18,071
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
The issue at lower flow rates is usually caused by spring loaded valve such as those in check valves and heater bypass valves. The valve opening is determined by the water velocity and the lower the velocity, the smaller the valve opening which changes the plumbing curve (i.e. moves it to the left or lower flow rates). But for most of the RPM values, Curve-A is sufficient.
The other problem is flow meters tend to get more inaccurate at lower flow rates as well and Blue-Whites are the worst. They have an accuracy specification as a percentage of full scale. But I would prefer to use the flow rate reported by the pump display as I believe it is more accurate than the Blue-White but the WF doesn't report flow rates.
Curve-B would be a bit closer at 1400 RPM and have an operating point of 17 GPM with a power usage of 111 watts and an EF of 9.1. So a bit worse than Curve-A but not by much.
Maybe the OP can try that speed and report the pump display of watts and meter GPM to see for sure.
Run the pump at several speeds including the lowest possible and then we can curve fit to a cubic and see where the y-intercept ends up. This will confirm that the pump is reporting true power or only motor power.
Last edited: