Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 7 of 7

Thread: PVC size

  1. Back To Top    #1
    orthofish's Avatar
    Join Date
    Jan 2009
    Location
    Northern Middle Tn.
    Posts
    561

    PVC size

    Is there any advantage/disadvantage to haveing 2" PVC on the suction side and 1.5" on the return side??
    Lynn

    16x38 FG, 20,400G, 1HP/2sp Tristar pump, Hayward 425sq ft cart. filter, Pro Logic4, SWCG, 3 returns, 2 main drains, 1 skimmer, 4 Pentair deck jets, Hayward Phantom pressure cleaner/booster pump, TF-100 of course :-)orthofish-s-pool-build-finally-t13179.html

  2. Back To Top    #2
    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    9,918

    Re: PVC size

    Pumps prefer lower head loss on the suction side vs the return side so normally a large pipe size is used on the suction side. However, I would go with at least 2" on both suction and return.

    If you have only 1 suction line, then I would increase that to 2.5". More than one suction line, you can get away with 2" line unless it is a high flow application (e.g. spa, waterfall, etc). For that you might need 2.5" or even 3".

    A single 2" return line is usually enough but larger there would not hurt as well. Again, larger for higher flow applications.

    Given that larger pipe is not that much more expensive than smaller pipe relative to the total cost of the pool, it is worth it to upsize the pipe.
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  3. Back To Top    #3

    In the Industry
    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    28,409

    Re: PVC size

    Hi, Mark,

    I have (2) 2-inch suction lines coming from the pool. It makes sense to me to bring them together before entering the pump with a 2.5" pipe. However, the pump inlet only accepts a 2" fitting. Will I gain anything significant if I run the 2.5" into it? The 2.5" run would be only about 3-4 feet.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  4. Back To Top    #4
    orthofish's Avatar
    Join Date
    Jan 2009
    Location
    Northern Middle Tn.
    Posts
    561

    Re: PVC size

    I will have a skimmer and main drain, both with their own line. 2 returns and 2-4 deck jets.No other water features. Could possibly do solar panels down the road.

    One of the two PB I'm talking to said they used a flexable line from the main drain to out of the ground, and also used about a foot or so of this flexable line from the back of the skimmer and returns. They said it would allow for any settling of the fiberglass pool since just a small shift,1/8 of and inch, could cause a union to leak. Does this sould right?? They gave me a piece of the pipe. It appears to be quite strong but does have a bit a flex to it.
    Lynn

    16x38 FG, 20,400G, 1HP/2sp Tristar pump, Hayward 425sq ft cart. filter, Pro Logic4, SWCG, 3 returns, 2 main drains, 1 skimmer, 4 Pentair deck jets, Hayward Phantom pressure cleaner/booster pump, TF-100 of course :-)orthofish-s-pool-build-finally-t13179.html

  5. Back To Top    #5
    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    9,918

    Re: PVC size

    Quote Originally Posted by duraleigh
    I have (2) 2-inch suction lines coming from the pool. It makes sense to me to bring them together before entering the pump with a 2.5" pipe. However, the pump inlet only accepts a 2" fitting. Will I gain anything significant if I run the 2.5" into it? The 2.5" run would be only about 3-4 feet.
    3' of 2" pipe has about the same head loss as 9' of 2.5" pipe. In a typical plumbing system, there are several hundred feet of equivalent pipe length so the % change isn't likely to be much.

    If you need to replace that pipe anyway I would say go ahead but if you just want to do it to lower head loss then I would say it probably isn't worth the trouble.
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  6. Back To Top    #6
    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    9,918

    Re: PVC size

    Quote Originally Posted by orthofish
    I will have a skimmer and main drain, both with their own line. 2 returns and 2-4 deck jets.No other water features. Could possibly do solar panels down the road.

    One of the two PB I'm talking to said they used a flexable line from the main drain to out of the ground, and also used about a foot or so of this flexable line from the back of the skimmer and returns. They said it would allow for any settling of the fiberglass pool since just a small shift,1/8 of and inch, could cause a union to leak. Does this sould right?? They gave me a piece of the pipe. It appears to be quite strong but does have a bit a flex to it.
    So with two lines on the suction, 2" is probably ok and you can match that with a single 2" on the return and the pump should be happy.

    As for the flex pipe, it is useful where you might expect some significant movement. I have heard that they are making it much better these days and that some pools are being installed with all flex.
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  7. Back To Top    #7
    orthofish's Avatar
    Join Date
    Jan 2009
    Location
    Northern Middle Tn.
    Posts
    561

    Re: PVC size

    Thank you Mark.
    Lynn

    16x38 FG, 20,400G, 1HP/2sp Tristar pump, Hayward 425sq ft cart. filter, Pro Logic4, SWCG, 3 returns, 2 main drains, 1 skimmer, 4 Pentair deck jets, Hayward Phantom pressure cleaner/booster pump, TF-100 of course :-)orthofish-s-pool-build-finally-t13179.html

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •