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Thread: Plumbing pool are 90 degree angles allowed?

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    Plumbing pool are 90 degree angles allowed?

    I tried searching but came up dry. My PB proposes 2" schedule 40 pipe but when I asked about angles he talked about using some 90 degree piping. The pool will be small, about 5500 gallons with an intelliflo. Will this be o.k.?
    Plaster pool inground 22,000 gallons with spa. Pentair Intelliflo, IC40 salt generator, WiFi control/Easy Touch.
    Hayward 1.5 HP pump on 750 gallon spa. Sand filters. Auto chlorinator on spa. Auto water level. Dolphin M500. TF100 XL with Speed Stir

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    Mod Squad JohnT's Avatar
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    Re: Plumbing pool are 90 degree angles allowed?

    90s are about inevitable. They'll be fine. You don't want to go crazy with them.
    TFP Moderator
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    Re: Plumbing pool are 90 degree angles allowed?

    Thanks....
    Plaster pool inground 22,000 gallons with spa. Pentair Intelliflo, IC40 salt generator, WiFi control/Easy Touch.
    Hayward 1.5 HP pump on 750 gallon spa. Sand filters. Auto chlorinator on spa. Auto water level. Dolphin M500. TF100 XL with Speed Stir

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    Re: Plumbing pool are 90 degree angles allowed?

    See if he can find "sweep" 90s instead of standard 90s. Sweeps create less head for a few dollars more per 90.
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    Re: Plumbing pool are 90 degree angles allowed?

    I did all sweep/street 90s when I re-did my plumbing. Found it's a lot easier to prime now than before and I get a lot less air bubbles on the suction side.
    Clearwater, Florida

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    Re: Plumbing pool are 90 degree angles allowed?

    The only sch 40 sweeps 90’s that I’ve found are the ones for waste. They have a smaller glue area and a max operating pressure of about 25 psi (temps about 70 degrees F. would lower the operating pressure). So I would think they should only be used on the suction side.
    Screen enclosed 17K gal 16x30 IG with Diamond Brite finish, elevated 4 jet spa with spill over, Twin dolphin fountain, Hayward Ecostar pump[ Pentair intelliflo VS, Filter Sta rite Posi-Flo PTM 100, Aqua Cal heat pump, Tiger Shark QC robotic cleaner.
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    Re: Plumbing pool are 90 degree angles allowed?

    Your builder should be able to get them from his wholesale distributor... or, you can check local landscaping supply companies - Ewing Irrigation has the most awesome PVC connector section...
    ~45Kg Pool with attached Spa, NSP-72 DE, Minmax 400 Heater, Tahoe Blue Pebbletech, Jandy SWG via Aqualink RS-8, The Pool Cleaner (black)
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    CAPTAIN JAMES T. KIRK: "I'M SORRY. I CAN'T HEAR YOU OVER THE SOUND OF HOW AWESOME I AM" (Thanks to TFP!)

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    Re: Plumbing pool are 90 degree angles allowed?

    Or you avoid 90 degree bends by using using flex pipe...

    *donning flame suit*
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    Re: Plumbing pool are 90 degree angles allowed?

    It depends on the pipe length, flow rate and water velocity. You don't want to put the full flow capacity of the IntelliFlo through 2-inch PVC.

    I recommend a maximum of 63 GPM through a 2-inch PVC suction with any 90s, and 73GPM if the suction pipe will not have 90s.

    I recommend a maximum of 73 GPM through a 2-inch PVC return with any 90s, and 83GPM if the return pipe will not have 90s.

    You can use 2 45s instead of a 90 to avoid using 90s.

    What flow rate do you expect to use?
    What is the distance of the pump and filter from the pool?

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    Re: Plumbing pool are 90 degree angles allowed?

    You can use 2 45s instead of a 90 to avoid using 90s.
    Not to start an argument with you but, the head savings from using 2 45*s over 1 90* isn't very significant


    (I couldn't find my source for the 'insignificance' of the 2 45s [if memory serves it's ~ .43'] ) However, I did recover this gem which is similar to the original question
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

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    Re: Plumbing pool are 90 degree angles allowed?

    It kind of depends who's data you use. Some show 2 45's being the same as a 90 and some (Bell & Crane) show them being worse. If plumbed back to back, it would most likely be worse than a 90 due to the extra turbulence. Now if you can replace each 90 with a 45, then you can save on head loss but that requires creative plumbing.
    Mark
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    Re: Plumbing pool are 90 degree angles allowed?

    This reference shows that one 90 is equivalent to 5.7 feet of straight pipe and that one 45 is equivalent to 2.6 feet of straight pipe. That seems to indicate that two 45s would be equivalent to 5.2 feet of straight pipe, so slightly better.

    I think that the first key is not to exceed the velocity guidelines of about 6 to 7 feet per second for the suction and about 7 to 8 feet per second for the returns.

    I think that the second key is not to create excessive head loss. When determining head loss goals, it can be useful to understand terms like "Return on Investment", "The Law of Diminishing Returns" and "Net Present Value".

    For example, if it cost 100 dollars to increase the pipe size from 2-inch to 2.5-inch and the lower head loss would save 10 dollars per month in electricity to run the pump, then you would probably conclude that the return on the investment was worthwhile. This would means that the net present value of all future savings was greater than the increased cost (investment) today. This would be on the good side of the law of diminishing returns.

    Example 2, if it cost 1,000 dollars to increase the pipe size from 2.5 inch to 3.0 inch and the lower head loss would only save you 1 more dollar per month, then you would probably conclude that the return on the investment was not worthwhile. This would be on the bad side of the law of diminishing returns.

    To determine head loss goals, you should know factors such as the average and highest desired flow rate, pipe length, pipe costs including materials and labor for installing different size piping, pump cost as a function of head loss etc.

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    Re: Plumbing pool are 90 degree angles allowed?

    Quote Originally Posted by JamesW
    It depends on the pipe length, flow rate and water velocity. You don't want to put the full flow capacity of the IntelliFlo through 2-inch PVC.

    I recommend a maximum of 63 GPM through a 2-inch PVC suction with any 90s, and 73GPM if the suction pipe will not have 90s.

    I recommend a maximum of 73 GPM through a 2-inch PVC return with any 90s, and 83GPM if the return pipe will not have 90s.

    You can use 2 45s instead of a 90 to avoid using 90s.

    What flow rate do you expect to use?
    What is the distance of the pump and filter from the pool?
    Pipe length will be pretty minimal, guessing around 20 feet or less. Builder had mentioned using gentle nineties so I'm thinking that these are the sweep 90's.

    Not sure about flow. I had read a post that salt generator wants 50gpm but to turn over pool I can run much lower. I'll never need full flow for 5400 gallon pool.
    Plaster pool inground 22,000 gallons with spa. Pentair Intelliflo, IC40 salt generator, WiFi control/Easy Touch.
    Hayward 1.5 HP pump on 750 gallon spa. Sand filters. Auto chlorinator on spa. Auto water level. Dolphin M500. TF100 XL with Speed Stir

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    Re: Plumbing pool are 90 degree angles allowed?

    All of these sources show two 45s as having more head loss than a 90:

    http://plasticpipe.org/pdf/tr-14_waterf ... istics.pdf
    http://www.pdhengineer.com/courses/o/O-5002.pdf
    http://westerndynamics.com/Download/fri ... ttings.pdf
    http://www.edstech.com/design-tools.html
    http://www.pumpfundamentals.com/downloa ... apter3.pdf
    http://www.uni-bell.org/resources/Chapter%209.pdf

    So again, it depends on which source you use but from all of the sources I have seen, most have two 45s being worse than a 90. I had used Engineering Toolbox for numbers until I discovered that most engineering firms use numbers that are supported by the Crane studies. In fact, the equivalent length method has lost some favor amongst the experts as shown in this thread:

    http://www.eng-tips.com/viewthread.cfm?qid=173164
    Mark
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    Re: Plumbing pool are 90 degree angles allowed?

    5500 gallons, 20' away, you would not have any noticeable, or appreciable savings not using 90's or using sweeps.
    Unless plumber is purposely doing loop to loops with the pipe, dont concearn yourself with it.

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    Re: Plumbing pool are 90 degree angles allowed?

    Paramount recommend 2 x45 instead of a 90 when plumbing their PCC2000 main drain to the debris canister to prevent cavitation on the suction side.

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    Re: Plumbing pool are 90 degree angles allowed?

    Quote Originally Posted by ocular
    Paramount recommend 2 x45 instead of a 90 when plumbing their PCC2000 main drain to the debris canister to prevent cavitation on the suction side.
    Welcome to TFP!!

    Thank you for posting this

    I can easily see that 2 45*s are less likely to become congested by 'stuff' (that somehow bypasses the grate) than a 90*, which would lead to cavitation.

    Mayhaps this issue should be considered when plumbing suction lines and have the head accounted for, when planning the size of the pump and filter.
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

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    Re: Plumbing pool are 90 degree angles allowed?

    Good comment, Thats probably why they recommend two 45s rather than one 90 to allow debris, leaves and stuff thru to the basket canister rather than a significant increase in resistance per se.

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