@Dodger is going to be thinking…”oh, please not again”…sorry Dodger.
Gene, I am rewriting a previous post to you just to make sure people “get it”; unfortunately, it also reveals my rather obsessive beliefs about this topic (haha). That post was important because it contains one of the key,
actually measurable values to back up my view. Lots of times we have to "judge" results (does it look cleaner?)...this isn't one of those times...this is real, hard data.
My "experiments" have shown that at low RPMs, my IFCS is, in fact, a giant check valve. And, because of the way IFCSs operate, this is not unique to my system. I haven't yet been successful in convincing anyone to take measurements in their system to corroborate this, Dodger wouldn't play, haha. I keep hoping that someone else will try it, but it really doesn't matter because the data doesn't lie.
Gene, you indicate that you get 2psi "back pressure" when running your IFCS at low RPMs. That is exactly what I get, too. But that deceptively low PSI number should NOT be ignored. 2 PSI (at very low flow rates/RPMs) is actually a substantial "impediment."
In fact, in my system, it pretty much negates all the efficiency advantages of running a "high efficiency VSP" at low RPMs. Look at Energy Factor in the chart below.
For now, I am going to ignore this question (and it IS a valid question)…
Is it worth it? Cost/Gain/Trouble. But I will answer it for me…absolutely. For those having a new IFCS designed
@Poolmama! the incremental changes in cost are pretty much zero. YES Poolmama, you do want a method to take your IFCS “out of the loop”, but personally I wouldn’t count “stubbing your toes on the popups” as one of the reasons
.
For as much talk about VSPs and their efficiency on this site, I find it very strange (as an Electrical Engineer) that there is absolutely NO discussion about the underlying reason for this efficiency. They are efficient because they have the “capability” to move more water (GPM) at a lower cost (fewer watts) than other pumps. But if they are installed inappropriately, or in the wrong circumstances (many are due to the really simple example below), this efficiency “advantage” can be lost or substantially reduced…even in pools with very, very simple plumbing designs. People tend to look at the watts number and think they are saving money because it is lower…not really the case. VSP’s energy efficiency is a function of their
GPM/watts ratio, not because of their watts number.
Here is an example for a simple pool with a VSP, an adequately sized filter, 2 wall returns, and a skimmer: A factor as simple as having the wrong size opening (say 1/2” vs 3/4”) on the wall returns can easily cut your low RPM VSP efficiency number by more than half. It WILL cost that pool owner twice as much as it COULD to filter, chlorinate, & skim their pool than if he simply changed out his nozzles. Those nozzles (like our popups) introduce restrictions, and it doesn’t take much, to really impact a pump’s Energy Factor.
I’ve actually tested this example on my pool because I was experimenting with the Venturi nozzle heads…TOO restrictive, my EF (energy factor) was cut by more than half when running at low RPMs.
Who says, “check your wall return nozzle sizes” when a poster excitedly posts that they have installed a new VSP and are going to save lots of money? No-one…it never occurs, except in those rare situations where those posters realize that something is not quite right with their system…and usually they are looking at their GPM numbers…something that is almost considered sinful on this site, haha. But, GPM is the key to a VSPs Energy Factor, and it is really easy to screw it up.
Efficiency improvement is one factor (cost), but in my case it’s actually not the driving issue for my passion. Saving an additional $2/month (off my normally $10/month pool electrical bill) is not why I am so adamant about this.
Effectiveness of my IFCS has improved dramatically with this change (unfortunately, effectiveness can NOT be scientifically measured).
Because I bypass the IFCS popups, the much higher water flows that I get when low speed skimming/filtering (@1200 rpm) really does make my pool cleaner. Skimming is FREE and, with the change, it skims at a much higher GPM for roughly the same cost. It is more efficient and
more effective to collect debris on the surface than it is to let it fall to the pool floor where the IFCS randomly pushes it around (at a high cost, “high pressure) before it is removed.
So once again, I am going to post my ACTUAL, measured numbers to show the impact of being able to “bypass” my IFCS by using 100% return to the wall returns during low speed skimming/filtering. By the way, some IFCS’s are not even designed with the ability to “add” this capability (PoolMama! take heed). That is a huge mistake in my mind.
| RPM | GPM | Watts | mPSI | fPSI | Energy Factor |
| Returns through Popups | 1207 | 11 | 140 | 2 | 2 | 4.7 |
| Returns through Popups | 1035 | 9 | 136 | 2 | 2 | 4 |
| Returns through Wall Returns | 1207 | 35 | 161 | 0 | 0 | 13 |
| Returns through Wall Returns | 1035 | 28 | 136 | 0 | 0 | 12.3 |
I know Energy Factor isn’t discussed on this site (mainly for the reason I stated…you need to know your GPM). But take a close look at it in my chart. It really is THE determining factor for VSP efficiency.
Finally, I will state another time that to take full advantage of a VSP’s efficiency and effectiveness in a system with an IFCS, it really requires automation to change those valve settings when you change your pump RPMs from cleaning (high rpms) to skimming/chlorinating/filter (low rpms). I can’t imagine doing this manually each day, or possibly every few days if that is how you choose to run your IFCS.
Sorry for all the wordiness…based on my experiments with my IFCS, this is one of the simplest and measurable ideas that I have about making your IFCS work well. I’m retired and have time to spend on this (one of my current) hobbies. But, I perfectly understand that these discussions don’t interest many…I will try to minimize these long, boring lectures.
