Has anyone hooked a flow meter to a pool with an Intelliflo?

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Christian

Christian

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Jul 19, 2012
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I have seen all the calculations and am firmly aware that the flow rates provided by Pentair are not very accurate. I'm also familiar with the formula for figuring out your flow rate. I'm just curious, has anyone actually hooked a flow meter to their pool and seen the real flow rate at different RPMs?
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

But, aren't the flow rates a function of head loss ... which is different for every pool. So, the flow rate at a given RPM will be different for every setup ... It might be interesting to see examples for different pools, but that will not likely offer up anything definitive to tell people who may be considering a certain pump.
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

True, I'm mainly looking for someone who has actually hooked up a flow meter so I can compare their results to what the charts say their results should be so I can see how far off they really are.
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

This may not be what you are looking for but the CEC has a database of direct measurements done on the Intelliflo, as well as other pumps, on three different plumbing curves and at two speeds each. Only 6 data points per pump but this is what I use to generate estimates at other RPMs and plumbing curves using quadratic interpolation (aka pump affinity laws).

You can find the data here:

http://www.appliances.energy.ca.gov/AdvancedSearch.aspx

I also have a shared version here:

https://docs.google.com/spreadsheet/ccc ... LRHc#gid=0


Also, Richard (aka Chem Geek) had done a series of measurements with the VF. However, this is not with a flow meter but using the VF flow rate readout:

calling-all-pool-owners-tell-me-about-yours-t1713-20.html#p25669


But one thing to keep in mind is a typical residential flow meter is not all that accurate. They are usually speced at 10% of the full scale which can be 10 GPM for a 100 GPM meter. To get accuracy, you have to spend a lot of money.

I am curious to what charts you are referring? Because I found the published head curve to be fairly accurate and match the results of the CEC measurements to within a few percent.
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

I investigated putting a flow meter on my pool last year, the responses from this forum were that they had an error of 10%, so that pretty much killed that idea.
Not sure if that is applicable to this thread, just wanted to put it out there.
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

I am the CEO of H2flow Controls and last year we launched a new flow meter that has since become the first and only flow meter to be certified and tested by NSF50. The average accuracy of our Patent Pending FlowVis unit was found by NSF to be just 2.01% Unlike other flow meters, it can be installed right next to other fittings such as elbows, 'T's' or 45's without any detrimental impact to its accuracy. The unit can be retrofitted to an existing Jandy Check Valve or it can be purchased as a complete flow meter / check valve combination.

The pool industry has long sought a reliable, affordable flow meter that could be installed next to other fittings. Rarely if ever is there 15 x pipe diameter of straight pipe to install flow meters.
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

I always am curious what the real value of learning an accurate flow rate is with BBB. We recommend running the pump enough to have clear water - with an Intelliflow what is the purpose of getting accurate flow rate data?

A side conversation on reactive approaches and how long to run the pump has been moved to here. JasonLion
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

Christian I have a commercial application that we installed two Intelliflo VS pumps not too long after they were available and the charts that Pentair published are fairly accurate. To appease the health dept. required flow meters and even giving room for error there were reasonably close.
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

Thanks for the info swimcmp! I'm curious because most of the people I've seen on here like to run their Intelliflo around 1000 RPMs. If the Pentair charts are accurate you would get almost no flow on that setting. Can you shed any light on that for me?
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

Christian, to use a pump curve, you need to know the head. Without seeing the plumbing in the ground (how many elbows, how much straight pipe, how many tees, branches etc.), it is a pure guess.
 

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Re: Has anyone hooked a flow meter to a pool with an Intelli

Christian, which curves are you looking at?

CEC Test data shows the following operating points for 800 RPM:

Curve-A: 18 GPM
Curve-C: 24 GPM


But here is the published head curve which shows 0-30 GPM (depending on head loss) at 690 RPM:

Intelliflo.jpg
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

Ok, so am I reading the chart wrong? Looking at 690 RPM it doesn't even have a rating above 5 feet of head. So what does that mean? At 40 feet of head will my flow at 690 RPM be 0?
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

Plumbing head loss is not a constant with RPM and there will never be 5 feet of head at 690 RPM. Head loss is proportional to the square of the GPM so as the RPM drops, the flow rate drops and head loss drops too. So at half speed, head loss drops by a factor of 4. At 690 RPM, head loss is only 4% of full speed.

So for example:

Assume the operating point at 3450 RPM is 100 GPM @ 75' of head.

At 690 RPM, the new operating point will be 20 GPM @ 3' head.
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

Ahh, ok. Thanks! I'm still trying to figure out the basics of flow rates and such so I can help out customers with questions, and there is a lot to learn! Now I see the glaring blind spot I had! I didn't realize that head was variable. I was told to calculate head by the distance from your pool drain to your equipment pad!
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

Calculating head loss is not trivial exercise and the length of pipes is only a small factor. The majority of head loss occurs in the fittings and equipment, especially valves, filters and heaters. Unfortunately, accurate head loss data is hard to come by for most equipment.

However, measuring head loss is much easier to do with a pressure and suction gauge. Once you have the head loss at a specific RPM, then you can calculate the head loss/flow rate at any other RPM.
 
Re: Has anyone hooked a flow meter to a pool with an Intelli

I actually have a digital flow meter installed on a dedicated long pipe after an intelliflow VS with a relatively new pool and large DE filter. All sorts of things impact efficiency of the pump, including how much inflow is coming from skimmers versus main drains, whether solar is active, and whether deep heating is going on, angles and sizes of various pipes, how much piping you have and how far the equipment is from the pool. In general, I try to keep gpm between 30-40pm as this is the minimum required to keep SWG, intellichem, solar, and heat pump happy.

Just general numbers:
Normal Minimal Energy Use Filtering Speed that keeps skimmer happy, 1650rpm, 32gpm, <300W
Solar Heating Speed (750 sqft of panels on double story house), 2300rpm, 38gpm, ~710w (treated as the high filtering speed each day to ensure pool surface is cleaned of leaves/etc).
Backup Heating via heat pump(rarely active), 2000rpm, I haven't checked gpm for this in awhile but I think it was around 37-39gpm, don't remember watts.

Pump is on for 12hrs/day, 7hrs solar and 5hrs filtering. The long runtime is mostly to accommodate the intellichem and that we mostly swim in the evening while the pump has to run during the day to get cheap heating via solar.
 
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