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Thread: Pool Suction wrong size!... Now what?

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    tsunami's Avatar
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    Skimmer Port Sizes

    All of the skimmers that I've seen so far have 2" ports. I don't know, but there may be other sizes.

    What if the suction for the main drains are supposed to be 2 1/2"? Would you install the 2 1/2" for the drains and reduce it at the skimmer port, and also run the 2 1/2" from the pump and reduce it at the skimmer?

    Wouldn't you be choking the line off that way?
    40 X 26 Free Form Pool with attached 9 X 7 Spa raised 18" with 8 Jets and Spillover, and an Art Rock Waterfall/Grotto with accent rocks, 26,000 gallons
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    tsunami's Avatar
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    Pool Suction wrong size!... Now what?

    While pumping out the rain water in the pool, I noticed that the pipes stubbed out for the main drain looked smaller than the others. Our plans called for all suction lines to be 2 1/2".

    Throughout the new pool build, I took a lot of pictures. So I went back to the pictures to see what I could find. It looks like the line from the main drain to the skimmer is 2" instead of 2 1/2". I believe it's also 2" going all the way back to the pump.

    The problem is that the shotcrete and masonry is done. I don't know the reason for the mix up, maybe a mis-communication? Both the spa suction and the waterfall suction are 2 1/2".

    I haven't brought it up to the PB yet. What can we do?
    40 X 26 Free Form Pool with attached 9 X 7 Spa raised 18" with 8 Jets and Spillover, and an Art Rock Waterfall/Grotto with accent rocks, 26,000 gallons
    Intelliflo VF-3050 for Pool, VS-3050 for Spa Jets, VS-3050 for Waterfall/Grotto, Quad DE 80, 400K BTU Mastertemp, Intellitouch i7+3 w/ iS10 10 Function Spa-Side Remote, Intellichlor IC40 Salt Chlorinator, Telephone Remote, 2 Intellibrites for Pool/ 1 for Spa, Solar Panels on 2 story Roof w/ 75% coverage
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    Re: Skimmer Port Sizes

    I have merged these two topic together. You will get better answers by giving us as much context as possible all in one place. JasonLion

    There are a number of answers, depending on what your goals really are. It mostly depends on what you mean by "supposed to be 2 1/2".

    Really understanding what is going on with plumbing can get complicated, though often enough the details don't actually mater. If you just want a simple answer you should tell us more about what you are trying to do. If you want to understand what is really going on you should read Hydraulics 101 - Have you lost your head?.

    Using 2 1/2" pipe for the main run and then narrowing it down to 2" for a short distance is very nearly as good as using 2 1/2" throughout. In other situations, it might be just as good to run more than one 2" line, each going to a different skimmer and thus get a very similar effect. It is also perfectly plausible to use 2 1/2" pipe on the main drain and 2" pipe on the skimmer. It all depends on what you are trying to achieve.
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    Re: Pool Suction wrong size!... Now what?

    There is rarely any need for the main drain to be 2 1/2", 2" is usually just fine. It is typically much more important for spa and waterfall plumbing to use larger pipes. To give you a detailed answer about the plumbing requires knowing many more details of your setup. Chances are good that everything will work just fine, though if the waterfall is intended to draw from the main drain there could be a problem. Given that the shotcrete is done already, there isn't any practical way to change it.

    There is also a contractual issue. If you mean the contract states that 2 1/2" plumbing will be used, then you have a case for getting concessions from the builder in other areas, cash back or extra features installed for free, because of their failure to live up to the terms of the contract.
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    Re: Pool Suction wrong size!... Now what?

    This is my first pool, so I have a lot to learn. I'll check out that article.

    My goal is a pool with efficient plumbing to help keep energy costs down.

    The pool is a 40'x26' freeform with a 9'x7'spa that spills over into the pool. There's also a 5' waterfall/grotto. The contract calls for all suction lines to be 2 1/2", a VS-3050 for the pool, Quad DE 60, Master Temp 400,000 BTU heater, 2hp whisperflow for the spa, and another 2hp whisperflow for the waterfall, solar panels, intellitouch controls, and one skimmer.

    I talked to a pool renovator today about the situation. He said: that there's not much suction coming from the main drains. You get more suction from the skimmer. The skimmer ports are 2" anyway, so the 2" from the main drain to the skimmer should be sufficient. If he were me, he'd have the PB replace the 2" from the skimmer to the pump with 2 1/2".

    The decking is not in yet, so it shouldn't cost them that much.

    Here's a pic of the set up @ the skimmer: The main drains are not shown, but you can see the 2" coming down from the skimmer to the drains. The 2 1/2" line in the middle is the suction for the waterfall, and the 2" line at the bottom I believe is the deep heat return.

    40 X 26 Free Form Pool with attached 9 X 7 Spa raised 18" with 8 Jets and Spillover, and an Art Rock Waterfall/Grotto with accent rocks, 26,000 gallons
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    Re: Pool Suction wrong size!... Now what?

    tsunami,

    As I had posted on Gardenweb, a single 2.5" line will have about the same head loss as two 2" lines. So if the main drains are plumbing into the skimmer and you have only one 2" line going back to the pad, you have two choices.

    If the PB can get to the skimmer, you mentioned it is now in gunite, he could separate the lines and run two 2" lines back to the pad. However, if he cannot get to the skimmers, then replacing the single 2" line with a 2.5" line where he can, should be nearly as effective.

    It would be better to have two lines but if it too late to do that, go with a single larger line.
    Mark
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    Re: Pool Suction wrong size!... Now what?

    Quote Originally Posted by mas985
    tsunami,

    As I had posted on Gardenweb, a single 2.5" line will have about the same head loss as two 2" lines.
    Yes, and I appreciate your input. As I posted on GW, I don't have the schematic for the plumbing. So right now, I'm just second guessing the plumbers. Maybe there's a combination of pipe's that will give it more flow. But since it says 2 1/2" suctions, I was expecting to see it at the drains.

    Quote Originally Posted by mas985
    If the PB can get to the skimmer, you mentioned it is now in gunite, he could separate the lines and run two 2" lines back to the pad. However, if he cannot get to the skimmers, then replacing the single 2" line with a 2.5" line where he can, should be nearly as effective.
    I'm not sure if I understand you correctly. Breaking the gunite around the skimmer might be a head ache, but are you suggesting that he "t" off from the 2" coming up from the main drains, so you have 1 2" going directly back to the pump in addition to the original 2" going thru the skimmer back to the pump?

    I know that there's another 1 1/2" dedicated line for the cleaner. It's a Hayward Navigator, and I believe it's a suction type cleaner. Would that help? Maybe they'll tie into the 2 1/2" suction for the waterfall at the pad. Is that a possibility? I'll find out more when I talk to the PB. I just wanted to get unbiased solutions in case they did make a mistake.
    40 X 26 Free Form Pool with attached 9 X 7 Spa raised 18" with 8 Jets and Spillover, and an Art Rock Waterfall/Grotto with accent rocks, 26,000 gallons
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    Re: Pool Suction wrong size!... Now what?

    Quote Originally Posted by mas985
    If the PB can get to the skimmer, you mentioned it is now in gunite, he could separate the lines and run two 2" lines back to the pad.
    I think he meant that if they could get to the bottom of the skimmer to cut the pipe where the Main Drain line enters the skimmer, cap the line into the skimmer, and put an elbow on the pipe coming from the main drains. Then they'd run a seperate 2" line soley for the main drain back to the equipment pad where it would have its own valve and be Tee'd into the suction plumbing. This is usually the perfered method because you can Isolate your Main Drains and pull only from them if you want to or if you need to (like draining below the skimmers).

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    Re: Pool Suction wrong size!... Now what?

    Quote Originally Posted by launboy
    I think he meant that if they could get to the bottom of the skimmer to cut the pipe where the Main Drain line enters the skimmer, cap the line into the skimmer, and put an elbow on the pipe coming from the main drains. Then they'd run a seperate 2" line soley for the main drain back to the equipment pad where it would have its own valve and be Tee'd into the suction plumbing. This is usually the perfered method because you can Isolate your Main Drains and pull only from them if you want to or if you need to (like draining below the skimmers).
    Exactly
    Mark
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    Re: Pool Suction wrong size!... Now what?

    Thanks for clearing that up guys. I'm hoping to avoid breaking the gunite.

    I noticed that at the manifold above ground, all pipes are 2". Where the VS 3050 will be are the Spa Suction, Spa Return, Skimmer, Pool Suction, Pool Return, and Deep Heat. On the other end of the manifold where the 2 Whisperflow Pumps will be are the Waterfall Suction, Waterfall Return, Booster Suction, and Booster Return.

    When the pool is in the cleaning/filtering mode, wouldn't the VS be drawing and returning water from both the spa and pool? If so, when figuring out if this pool flows water efficiently, you'd have to also take into account the size of the spa suction and return lines as well as the suction cleaner, right?
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    Re: Pool Suction wrong size!... Now what?

    The plumbing should set up using 3 way valves such that the pump will draw from either the pool or spa but not both. Otherwise, you won't be able to heat the spa. When heating the spa, the spa needs to be isolated from the pool so the pump will draw from the spa but then return the heated water back to the spa.

    In pool mode, the pump will draw from the pool and return to the pool. However, many contollers will allow a spillover mode as well which will draw from the pool and return to the spa and thus spilling over into the pool.

    Your plumber should also put valves in-line with each suction and return pipe so that you can make adjustments for flow if necessary. Without a drawing or pictures, its hard to say what your PB has in mind for a configuration. You might want to consult with him and get some details before he gets too far.
    Mark
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    Re: Pool Suction wrong size!... Now what?

    The PB's going to call me back to discuss the plumbing.

    Here's a pic of the manifold. I noticed that the spa suction is 2". The spa return is 2" at the manifold and at some point steps down to 1 1/2". The booster pump suction and return are 2 1/2" and 2" respectively.

    40 X 26 Free Form Pool with attached 9 X 7 Spa raised 18" with 8 Jets and Spillover, and an Art Rock Waterfall/Grotto with accent rocks, 26,000 gallons
    Intelliflo VF-3050 for Pool, VS-3050 for Spa Jets, VS-3050 for Waterfall/Grotto, Quad DE 80, 400K BTU Mastertemp, Intellitouch i7+3 w/ iS10 10 Function Spa-Side Remote, Intellichlor IC40 Salt Chlorinator, Telephone Remote, 2 Intellibrites for Pool/ 1 for Spa, Solar Panels on 2 story Roof w/ 75% coverage
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    Re: Pool Suction wrong size!... Now what?

    That manifold is temporary and used to pressure test the lines. The PB should remove that and reconfigure for the equipment and the control you need.
    Mark
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    Re: Pool Suction wrong size!... Now what?

    Quote Originally Posted by mas985
    That manifold is temporary and used to pressure test the lines. The PB should remove that and reconfigure for the equipment and the control you need.
    Yes, I realize that. I posted it to show the location of the risers in case you were interested. It's hard to see but their labeled at the top. I'm guessing that all the plumbing above ground is usually done in 2", even though the pipe may be bigger?

    For the spa, which is around 35 feet away, would the 2" suction and 1 1/2" return be sufficient since it's probably under 1000 gallons? I've read about how to size a pump, but in this case we know the pump is a variable speed, so how would you figure if the pipe size is correct? Would you figure on keeping the feet per second below 5 and then figure out the flow given the number of gallons?
    40 X 26 Free Form Pool with attached 9 X 7 Spa raised 18" with 8 Jets and Spillover, and an Art Rock Waterfall/Grotto with accent rocks, 26,000 gallons
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    Re: Pool Suction wrong size!... Now what?

    The key issue with the spa plumbing is the number of jets and the design flow rate of the jets. If you have, for example, four low flow jets than 1 1/2" plumbing can work. If you have, for example, eight high flow jets then you are quite likely to have trouble with 1 1/2" plumbing.

    With a variable speed pump, larger pipes lower your total electrical costs for running the pump, because you can run the pump on a lower speed and still get the flow rate you want. As the pipes get smaller, you need to turn up the speed on the pump. Eventually, you get to the maximum speed on the pump. If you need to turn it up from there you have a problem.

    Your pipes are smaller than I would ideally want to see for saving electricity purposes. Spas are often plumbed with 2 1/2" or even 3" pipes these days. Depending on how many and what kinds of jets you have in the spa your current pipes might work, but use more electricity than is ideal. However, if you have a relatively high number of jets or your jets require relatively high flow rates then there could be more obvious problems.
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    Re: Pool Suction wrong size!... Now what?

    The spa has 8 jets and also it's own booster pump(proposed 2 hp Whisperflow) with 2 1/2" suction and 2" return. In addition, the spa has a 2" suction and a 1 1/2" return.

    If I'm not mistaken, the spa suction and return are plumbed to the VS with the pool, and the booster suction and return power the jets. In this case maybe the 2" suction and the 1 1/2" return are sufficient or should it be bigger? Here's a couple of pics:


    40 X 26 Free Form Pool with attached 9 X 7 Spa raised 18" with 8 Jets and Spillover, and an Art Rock Waterfall/Grotto with accent rocks, 26,000 gallons
    Intelliflo VF-3050 for Pool, VS-3050 for Spa Jets, VS-3050 for Waterfall/Grotto, Quad DE 80, 400K BTU Mastertemp, Intellitouch i7+3 w/ iS10 10 Function Spa-Side Remote, Intellichlor IC40 Salt Chlorinator, Telephone Remote, 2 Intellibrites for Pool/ 1 for Spa, Solar Panels on 2 story Roof w/ 75% coverage
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    Re: Pool Suction wrong size!... Now what?

    Alright, that makes a lot more sense. The smaller suction and return to the main pump are used for heating the spa, which doesn't need the high flow rates that the jets require. This is a fairly standard setup. Larger pipes could increase the efficiency of your plumbing, but everything should work well enough the way it is.
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    Re: Pool Suction wrong size!... Now what?

    I talked with both the foreman and the big boss a couple of times, and here's their take on it. They said that it's fine the way it is. Concerning the spa, they said that the spa suction(2 in.) and spa return(1.5 in.) will only be used to heat the spa, and uses basically a low flow, so big pipes aren't needed here. Also, the suction line from the skimmer(2 in.) and the suction line from the cleaner(2 in.) are also fine because you don't need hi flow to circulate and clean the pool. They also said that the water features(spa jets and waterfall) is where the high flow is needed and require larger pipe(2.5 in. suction and 2 in. return).

    The explanation for the size of the pipe to heat the spa makes sense to me(I think), but I think the pool suction side is lacking with just 1 skimmer at 2" and a dedicated cleaner line at 2"(stepped down to 1.5" for most of the run). So, I met with the big boss face to face and let him know that I wasn't happy with the pool suction, and since the contract called for 2.5", I want the skimmer line replaced. He said that he had no problem with it and wanted me to be happy. I told him that I wanted the line replaced from the equipment pad to the skimmer without breaking the gunite that it's encased in, but instead of running 2.5", I want 3" and agreed to pay the difference in materials.
    40 X 26 Free Form Pool with attached 9 X 7 Spa raised 18" with 8 Jets and Spillover, and an Art Rock Waterfall/Grotto with accent rocks, 26,000 gallons
    Intelliflo VF-3050 for Pool, VS-3050 for Spa Jets, VS-3050 for Waterfall/Grotto, Quad DE 80, 400K BTU Mastertemp, Intellitouch i7+3 w/ iS10 10 Function Spa-Side Remote, Intellichlor IC40 Salt Chlorinator, Telephone Remote, 2 Intellibrites for Pool/ 1 for Spa, Solar Panels on 2 story Roof w/ 75% coverage
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