Los Angeles Remodel, or Can a regular plumber do a repipe?

[WalkerTribe7]

We

Thanks Mark,

Can you tell me how you did the math?

Also, for the plumbing on the features, I was under the impression that I had two options to balance the output.

1. The plumbers that have seen the job so far recommended running a 1.5" line to each water feature from the equipment pad, with ball valves at the pad to control the flow to each.

2. I saw a picture online that seems to suggest that you can hydraulically balance the output by looping plumbing around from one inlet straight in its center. Can this method be used for 5 outputs over a 30 foot distance or does the concept fail?

View attachment 94148

We are doing #1 with our Bobé Water features. It’s currently covered due to rain. But once it clears, I will take some pictures. But our four water features have their own line from the equipment. Three of mine are grouped together and one in the corner, so I have the ability now to keep all four on at the same time or turn off the large one and keep the three smaller ones going (or vice versa). All four water features are being run off their own 2hp vsf. Our three “u” scuppers are 18” long and the corner is a 3’ Radius.

 

[Xizenta]

We



We are doing #1 with our Bobé Water features. It’s currently covered due to rain. But once it clears, I will take some pictures. But our four water features have their own line from the equipment. Three of mine are grouped together and one in the corner, so I have the ability now to keep all four on at the same time or turn off the large one and keep the three smaller ones going (or vice versa). All four water features are being run off their own 2hp vsf. Our three “u” scuppers are 18” long and the corner is a 3’ Radius.

Cool, love to see it.

 

[Xizenta]

It is a bit complicated. Head loss is related to the number/type/size of fittings, pipe length/size, return orifice size, suction port size, other equipment, etc plus the flow rate going through the plumbing (i.e. pump size). But head loss does not equal the equivalent pipe length (common misunderstanding). A simple way of explaining the process is to first determine the plumbing head curve. Plumbing does not have a fixed head loss and it is dependent on the flow rate. The higher the flow rate, the higher the head loss. So if you can determine the plumbing head curve, you can plot that over the pump's head curve and where they intersect is the operating point. So the operating point is dependent not only on the plumbing but the pump you put on the plumbing. This where a lot of web sites fail at head calculations.

There are actually many options. #1 will work but requires extra plumbing. #2 improves the situation but does not guarantee equal flow rate.

If you want to ensure equal flow rate, go with #1 or use at least 2.5" pipe for the loop in #2. But there are multiple ways of feeding returns. Here is an analysis I did some time ago on the different ways and their performance. Plumbing Loops

In general, as pipe size increases, there is less of a difference between the options. This is because as pipe size increases, the head loss is reduced between the returns which is the cause of the imbalance.

Mark,

Thanks for the link and for your research on that. I spent a lot of time looking for something like this last week and was unable to find it. It's super helpful.

At this point I haven't found a better self-priming pump than the one you recommended. It was a pretty expensive pump and running 5 independent lines to the scuppers seems unfeasible. So I think what I'm going to do is just be less ambitious and take three of those scuppers instead of five. After seeing your post I think I basically understood how to calculate head correctly in the first place. I started with the amount of flow I wanted (150) and tried to calculate based on that. Unfortunately, the tables I was referencing really only showed friction loss based on 70 gpm and like 50 gpm, so I just had to kind of assume things would be worse without knowing to what extent.

I think if I use three of the scuppers along that raised bond beam I'll need 90-95 or so GPM and can run three 1.5" lines with the valves at the equipment pad. The Pentair High Flow Challenger at 1 horsepower will supposedly give me around the output I am looking for.

You say it should have its own suction line from the pool. Are you thinking I should put some drains on the wall closer to the equipment pad? I thought about that but it seems like the TDH on this circuit might be too low that way if I bypass the filter, heater, etc. If I were interested in taking from the deep end of the pool, is there some way I could plumb to the drains there while leaving them available for the other circulation circuit too?

 

[mas985]

Putting the suction ports on the equipment side is actually a better choice. Lower head loss on the suction side of the pump is always a good thing.

However sharing the line with the filter pump can be done but you would need to size the suction pipe for both flow rates at the time which will make the pipe very big.

Having a separate suction line is a better choice IMHO.

 

[Xizenta]

Putting the suction ports on the equipment side is actually a better choice. Lower head loss on the suction side of the pump is always a good thing.

However sharing the line with the filter pump can be done but you would need to size the suction pipe for both flow rates at the time which will make the pipe very big.

Having a separate suction line is a better choice IMHO.

Is there any concern that having the suction ports near the equipment side of the pool will lower the head of this plumbing circuit below the handling capacity of the pumps we are discussing? I would like to be able to use the 1hp Pentair Challenger High Flow. The chart says below 25 is not happening. I know less than 25 feet of head is uncommon in a pool but in this case with the filter and heater omitted and a very local suction port I suppose it's possible?

Also, hypothetically speaking, having a return line flow into just plain air (as in a waterfall), should be less restrictive than flowing into a water filled reservoir right? Are we accounting for that in our math? So far everything I've looked at is treating the applications the same.

 

[lester58]

Hey guys. Long story short, I'm trying to do a remodel to a 28k gallon pool in the San Fernando Valley.

Boy has it been hard finding a quality, affordable contractor. I have found someone affordable for tile and plaster as well as decking. What I'm concerned about is plumbing. As you probably imagined, most of the publicly listed pool contractors are general contractors who don't handle plumbing per se, but want to do the whole job. They can get someone for my job, but they want to add on their own profits. Not to mention, they also do not like the idea of doing partial work and leaving decking, coping, plaster, and tile to the guys I have already found and already trust. I need to find a plumber who can do a repipe, add a water feature, and connect my equipment. I'm having a terrible time of it.

My question is, are regular plumbers generally experienced in the installation of plumbing for pools, typically?

I would ask around at a few pool companies that you know ... or maybe a county next to you .... maybe there is a person who posted on their bulletin board or used to work for a pool company you might snag ....... sounds a little complex using 3 or 4 people to do this job ... Good luck !!

 

[mas985]

Is there any concern that having the suction ports near the equipment side of the pool will lower the head of this plumbing circuit below the handling capacity of the pumps we are discussing? I would like to be able to use the 1hp Pentair Challenger High Flow. The chart says below 25 is not happening. I know less than 25 feet of head is uncommon in a pool but in this case with the filter and heater omitted and a very local suction port I suppose it's possible?

Yes, that will be an issue with the High Flow pump and would force the pump into a run out condition. However, this would not happen with the waterfall version of the pump (AF series). If you want to use that pump, you would just have to add head loss to the return side and the easiest way to do that would be adjust the throttling valves on all three ports to not only balance the 3 scuppers but to prevent pump run out. Not very efficient but it works.

Also, hypothetically speaking, having a return line flow into just plain air (as in a waterfall), should be less restrictive than flowing into a water filled reservoir right? Are we accounting for that in our math? So far everything I've looked at is treating the applications the same.

That's true but in this case, it doesn't make that much of a difference. Because the scuppers use 1 1/2" feed lines there isn't much head loss in or out of water. But yes, that is taken into account.

But given you have only 3 scuppers now, why not run them with the primary pump? You won't need separate circulation when the scuppers are running anyway. Just use a 3-way valve to turn them on and off. You could automate the valve as well.