Question about Pump Installation

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Z

zethacat

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LifeTime Supporter
Sep 23, 2013
810
Dallas-Ft. Worth Metroplex, TX
So I was reading over the manual for my new Intelliflo VS pump (011018) and noticed the part where it states this:

"Do not install 90 degree elbows directly into pump inlet or outlet. A valve, elbow or tee installed in the suction line should be no closer to the front of the pump than five times the suction line pipe diameter (i.e., 2 inch pipe requires a 10 inch straight run in front of the suction inlet of the pump). This will help the pump prime faster and last longer."

Well, I have 2" pipe and there is definitely not 10" of straight pipe to the inlet of this pump. This isn't the first time the plumbers went against manufacturers specs. The first time was when they installed my heat pump right next to the pool pump and up against the wall of my house and then had to come back and move it 12" away from each. I wonder if they ever read the manuals for these devices. Obviously, they did not read the manual for Intelliflo and have installed an elbow 5" from the inlet. They also installed a tee 7" from outlet but I don't know if that's contraindicated as the wording above is a bit vague. But as you can see, the plumbing is tight over there to begin with (How moronic was it of them to block the suction outlet vertically with the return pipe!) If I did insist they re-install the pump with 10" straight pipe to inlet there would need to be some major re-arrangement. I created that little flagstoned space in between the heater and the pump so I can easily get over there to work the timers, switches and pump. If they move the pump into that area, they will need to move the heater again, and then I may have to move my liquidator somewhere very inconvenient). Do I need to worry about this or am I overreacting and I should just forget about it and leave it the way it is? After bleeding air out of the filter it can sometimes take upward of 15-20 seconds to prime. I don't know if that is way beyond what it should be as I don't have anything to compare it to.

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The outlet does not matter. The inlet requirement is kind of outdated. Should not be a problem, especially if you do not run close to full speed. Just keep an eye on air in the pump or priming issues.

If it primes within a minute or so, that is fine.
 
When you say "especially if you do not run close to full speed" can you elaborate. Right now my liquidator is not flowing well at even 2800 RPM and the skimmers don't do anything at less than that anyway... I also like to ramp it up for the water slide. I am getting a new filter today , which should improve the flow a great deal but I would still like to be able to use max speed for water features and liquidator.
 
The higher the speed the more likely you are to have issues of turbulence due to the lack of straight pipe. But, like I said that is an outdated requirement and may not really be applicable to the newer pumps. Plus you have a 45 and not a 90 which is not as bad from a flow perspective.

There have been a few members who have had issues without enough straight pipe. I am sure there are many more that so not have problems.

- - - Updated - - -

So you have all 3 suction lines wide open ... that is certainly going to require higher speeds. You could mostly close off the floor drain to get better skimming.
 
That is an interesting concern:
Here is a copy/paste paragraph from the California pool building code. I agree that it is probably not worth trying to get it corrected at this point, but here is what one building code states: (sorry about the poor formating; there must be embedded codes that are eliminating proper spacing - the entire code can be found from an online search)

Measure 3 - Pipe DesignMeasure three addresses three pipe design issues: straight pipe run before pump,design pipe size and low head fittings. Straight Pipe Run at PumpThe first issue pertains to the recommendation by most pump manufacturers that alength of straight pipe equal to 4 to 5 pipe diameters must precede the pump. T hisrequirement is to reduce turbulence on the suction side of the pump that could lead tocavitation in the pump, increasing energy use and decreasing its effective life. Becausethe pump operates less efficiently and the flow drops off when the pump is cavitating, apump would have to operate longer to turn the same volume of water. Pumpmanufacturers estimate the energy impact is anywhere from 10 to 50%, and thatbetween 50 and 70% of the new pools are installed with insufficient straight
 
While the straight pipe issue does cause problems every now and then, it is almost never an issue. It is incredibly rare to actually see that much straight pipe, yet 99.99% of all installs never have an issue related to this. This is even more true with modern plumbing practice, which uses larger pipe diameters than were used in years past, which further reduces the odds of having a problem.

Air collecting slowly in the pump basket is normal for a variable speed pump running at a lower speed. The pressure inside the pump basket is lower than atmospheric pressure, allowing some dissolved gasses to outgas. At higher speed the air still collects there but the pump is able to pull the air through the pump. Only at lower speeds does it accumulate. This process is very slow and should never fill the pump basket more than about half full with air. More rapid air accumulation of air, and/or loss of prime, can be a sign of a suction side air leak.
 
I'm usually in the .0001 percentile of everything. Thing is, I haven't been running my pump at a lower speed. I run it at 2800 RPM right now because anything less and there isn't enough suction to pull the skimmer door open. Even at 2800 RPM the skimmer is barely sucking anything in. I do have a dirty filter but the filter is being replaced so I'm not going to bother cleaning it. I've even closed off half of the main drain and it doesn't seem to make much difference. When the pump started this morning there was no air in the basket, but when I checked a few hours later, a bubble was starting to form, and when I checked a little later, the bubble was getting bigger. It just doesn't make sense to me that the manual specifically states 2 inch pipe requires a 10 inch straight run if it were written for older plumbing. Is 2" considered old?
 

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Whatever problem(s) you are currently having, none of them sound like anything that could possibly have to do with the straight pipe before the pump issue.

An air bubble in the pump strainer basket is normal for that pump, unless it gets very large. If the bubble indicates a problem, then it indicates a suction side air leak. Regardless, it can't have anything to do with the straight pipe question

As for the weak skimmer flow, if it had anything to do with the straight pipe issue you would be hearing a very loud noise and a fair bit of vibration from the pump. It could easily just be the filter being dirty, or the skimmer weir being jammed. Whatever it is, unless you are hearing a loud noise and seeing lots of vibration, it has nothing to do with the straight pipe issue.

Even the mildest version of the straight pipe problem would cause problems priming the pump. If you aren't having problems priming the pump then the pipe leading to the pump is just fine.
 
So the Quad filter with the multiport valve actually doesn't fit in the same spot as the grid filter, so the guy is coming back tomorrow with everything he needs to move the pump and booster pump over to make room for it. And while he's at it, he's going to give that darned pump the 10" of straight pipe it needs. Bam! ;-) My PB is amazing.
 
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