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Thread: Pool plumbing question

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    Pool plumbing question

    Good morning all,

    I had the pool refurbished last fall. Everything is working as expected but I am running into a minor problem with the lines in to the pump.

    We had a new skimmer with new lines, and added a step with two jets.

    The way the skimmer was hooked up with 2 lines (no main drain). Both lines (1.5") as you can see go to the pump and everything else is normal. The issue I am having is that if I turn on both skimmers lines on, the water into the pump seems to cavitate as there is a lack of water coming in. If I run the separately there are no issues?

    Thoughts, suggestions. I can run them separately or even plug one and have it as an emergency line in the event that something should happen to the other line. I would rather more circulation.

    Thanks in advance,

    C
    Attached Images Attached Images
    Last edited by canuckpool; 08-25-2014 at 07:13 PM. Reason: remove pic to get more pic quota

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    mas985's Avatar
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    Re: Pool plumbing question

    It actually should be the opposite. When running both, the suction should be it's lowest and you should be getting the most flow rate. Did you look at the skimmer when you have both lines on? It could be drawing in air via a vortex.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Pool plumbing question

    mas985,
    thx for the reply. So I opened both up and it's running okay but still have some air in pump basket. Tried bleeding air from filter and still have some bubbles in pump, ~10% air.

    As far as the skimmer question, no vortex noted.

    If open only one line, I get no air; both lines draw air.

    Is it an issue or should I just enjoy the pool.

    Thx,

    C

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    mas985's Avatar
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    Re: Pool plumbing question

    It is probably a pump lid or drain plug air leak. Try a little pool lube on the gaskets and see if that helps.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    gtemkin's Avatar
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    Pool plumbing question

    The vortex in the skimmer basket seemed like the most likely cause. Did you check it with the skimmer basket removed? The basket might be hiding a path for air entry. Or possibly a weir door is sticking periodically and it wasn't sticking when you looked at it. I've noticed that at certain lower water levels skimmer and weir abnormalities come and go in an oscillating manner.

    Why did the pool builder use 2 separate lines to hook up the skimmer? Did the pool previously have a main drain?

    On a separate subject, I might suggest you limit opening and closing the left side skimmer valve. Those type of valves have very high operating forces and the one on the left is joined to the T fitting by a very short section of flex PVC. With much of the valve operating force being absorbed by that short flex-PVC joint, it seems like just a matter of time before a suction side leak starts.

    During a re-plumb job performed by my PB, he removed 3 relatively new Jandy valves and replaced them with the same valves you have. Everytime I turn one of those valves I kick myself for not having insisted he reuse the Jandys. Jandy's are a dream to turn in comparison.
    21K gal 16' x 40' in-ground pool built 1959, old school with Jacuzzi bronze pump, American Products 24" Sand Filter & Americana Multiport valve, Jandy Lite2 millivolt heater, Coverstar cover, and classic Kreepy Krauly.

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    Re: Pool plumbing question

    I'm looking at replumbing my intakes as well....
    Isn't this a "recommended against" layout? Doesn't this have the possibility of someone closing both valves and starving the pump?

    -Denny
    IG gunite 20k Gal (estimate), Nautilus NS-60 filter (D.E.), Single speed pump (unreadable nameplate - assume 1HP) on a crappy mechanical timer.
    And a worn-out Kreepy Kraully. TF-100.

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    gtemkin's Avatar
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    Re: Pool plumbing question

    Yes, I think you're right. Any time you use 2 separate 2 port valves instead of a single 3 port valve you have the possibility of closing off both input ports.
    21K gal 16' x 40' in-ground pool built 1959, old school with Jacuzzi bronze pump, American Products 24" Sand Filter & Americana Multiport valve, Jandy Lite2 millivolt heater, Coverstar cover, and classic Kreepy Krauly.

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    Re: Pool plumbing question

    Just to double check, when the handle is perpendicular to the pipe, the valve is closed. And, when the handle is parallel to the pipe, the valve is open.

    Why are there two lines? Are there two skimmers or are both lines plumbed into the bottom of one skimmer?

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    Re: Pool plumbing question

    Good morning all,

    Sorry I haven't replied but I have been away. I will now reply to all.

    Thanks,

    C

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    Re: Pool plumbing question

    gtemkin - Thanks for your reply. When I look in the skimmer basket it's all good, no vortex noted. I don't see the weir sticking shut and preventing water from entering. Can tell you why the builder used two lines, I guess since the original pool did not have a main drain, he thought he would plum two lines for me.

    I will take your advise RE: left side skimmer valve. The original problem I posted seems to be more prevalent when I used that valve.

    No leaks noted to date.

    - - - Updated - - -

    JamesW - Thanks for the reply.

    The opposite, when the handles are perpendicular they're opened, when parallel they're closed.

    One skimmer, he plumbed two lines as there wasn't a main drain and since the skimmer had two intakes he plumbed them. On the surface it seems like an okay idea but now that I am having issues it's not fun.

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    epro05's Avatar
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    Re: Pool plumbing question

    All the valves I've seen work like James said. Are you sure yours is opposite?
    27,500 gallon in ground gunite/plaster (1995). Attached Spa with fountain, spillway, and 2 lion heads streaming into the pool. Hayward pump and AO Smith UST1152 1.5 hp motor (single speed). Hayward 60 sq ft DE Filter (Model DE-6000). Kreepy Krauly cleaner.

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    Re: Pool plumbing question

    Another twist. Since my original post I have been trying different things (time permitting) and following advice from fellow members. The other morning prior to catching an early flight I walked outside only to find the pump cranking along but the pump basket having little to no water. All pressure in system was gone. Twice since then I have woken up to the system being empty, meaning little to no water in the pump. I have to re-prime it and it is all good. This am I took the pump apart to see if the impeller was damaged or if the seals were bad. See. pics. They don't appear to be bad.
    2014-08-23 09.03.55.jpg2014-08-23 09.04.56.jpg2014-08-23 09.07.31.jpg

    One other thing I have noticed is that things seem to happen when one of the two new jets plumbed in the new steps is opened, when this jet is opened I lose all pressure in the morning. My pump is on a timer which runs from 00:00-07: 00. I would have to wake up closer to midnight and prior to the pump starting to see if the system has lost pressure. Bad news is that these pipes are under the newly poured concrete and stones. Could there be a leak leading to one of the jets that is causing all these headaches?

    2014-08-23 09.39.42.jpg

    This is the water flow in the skimmer when both lines are opened? Is there a way to get rid of the weir, is that a good idea?

    Thanks to all who read and reply.

  13. Back To Top    #13

    Re: Pool plumbing question

    Those look like Praher ball valves. I'm pretty sure that the valves are closed when the handles are perpendicular to the pipe.

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    Re: Pool plumbing question

    Quote Originally Posted by JamesW View Post
    Those look like Praher ball valves. I'm pretty sure that the valves are closed when the handles are perpendicular to the pipe.
    That is correct.

  15. Back To Top    #15

    Re: Pool plumbing question

    Was part of the problem a misunderstanding of the valves being open or closed?

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    Re: Pool plumbing question

    Quote Originally Posted by JamesW View Post
    Was part of the problem a misunderstanding of the valves being open or closed?
    Hi JamesW,

    The main issue seems to be that one of the two skimmer lines in bringing air into the system. Not sure where to go from here. Luckily the one line is air free and performing optimally.

  17. Back To Top    #17
    mas985's Avatar
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    Re: Pool plumbing question

    In your original post, you said that you only get air when you have both lines on. Is this still the case and with either line on and the other off, there is no air?

    If so, I would still look at the skimmer while you have both lines on. The water level is very low and my guess is it is sucking in air. Basically, it can't handle the higher flow rate.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Pool plumbing question

    mas985, I'll look at it and report back.

  19. Back To Top    #19

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    Re: Pool plumbing question

    The last pic you posted of the skimmer with both lines open is the problem. It's pulling the water in to fast and creating a vortex that is introducing air.

    I'm to lazy to research it but it looks like your pump is a 2hp Pentair Whisperflo? If so then you may be oversized for only the one line. If it's 2hp single speed then you may need to start saving for a smaller pump or at least a variable speed one.

    They may make a vortex eliminator that you can put into your skimmer under the basket????
    26k gal, IG, Pebble Tec, DE filter/48sq'/144 GPM, 3hp Intelliflo running @ <1400 rpm 24/7

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    gtemkin's Avatar
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    Pool plumbing question

    Didn't someone post at one time that a tennis ball in the skimmer was a universal solution?

    Edit: Now I remember. Someone posted a link where a sand filter supplier had a video on how they worked. In that or one of the other videos on their site they mentioned the tennis ball trick to eliminate skimmer vortexes.
    21K gal 16' x 40' in-ground pool built 1959, old school with Jacuzzi bronze pump, American Products 24" Sand Filter & Americana Multiport valve, Jandy Lite2 millivolt heater, Coverstar cover, and classic Kreepy Krauly.

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