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Thread: Am I crazy?

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    Am I crazy?

    The answer is probably yes, but read on:

    My pool is now almost a year old and it's working fine. It was an owner-builder endeavor that went pretty well, but I've never been completely satisfied with the plumbing. The guy I hired to do the work wasn't great and it was clear his knowledge was limited to a small pool template. For those of you that have a pool-vac working off your filter pump you'll know that there is a balance between sucking from your skimmer/drain and sucking from the vacuum line. That sweet spot was pretty complicated for me to find and I solved the problem through automation (you'll see in the pic below), finding the right RPMs on my VS pump, and managing the flow on the 2nd skimmers valve gate. It works fine, but I'm thinking that I could increase the tolerances and improve efficiency overall by replacing some 2" valves and related piping with 2.5" or 3".

    In the picture you'll see that I have 4 lines on the suction side coming from my pool, and they all route through the filter pump:

    1. The Spa drain.
    2. The 1st skimmer and main pool drain. I've installed an actuator to close this valve when the vacuum turns on.
    3. The Vacuum
    4. The 2nd skimmer and another drain that is used to power a waterfall booster pump (just to the right)

    You'll see at the pad that I have 2.5" pipes coming from both pool drains (2 & 4) and a 2" pipe for the vacuum. They all scale into the 2" ID portion of each jandy valve and head towards my VS pump as 2". On the return side of the pump it starts as 2" and heads all the way back to the pool. It eventually scales down to 1.5" pipe supporting 4 inlets that each have 3/4 openings. I've always wondered if I replaced the manifold (the top section of 1,2,3,4) with 2.5" or 3" pipe all the way to the pump that I may see better performance. I'd be able to push more water through the system and allow for a bit more flexibility when tweaking the vacuum. It's worth mentioning that when my pump is running at 2750 my Jandy cartridge filter only sees about 10psi. Also, from reading this forum and looking at my actual pump manual I don't think the 2" in and 2" out config for this pump is recommended. At above 2750RPMs I do start to see some cavitation.

    Anyway, it's pushing winter here in SoCal and now is a good time to start messing with my pool. So... am I crazy to spend the 300 or so on parts, or do you think I may see some benefit? Thanks for your opinions and sorry for the long post!
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    Shelley
    Denver, CO

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    duraleigh's Avatar
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    Re: Am I crazy?

    I've always wondered if I replaced the manifold (the top section of 1,2,3,4) with 2.5" or 3" pipe all the way to the pump that I may see better performance.
    Welcome to the forum. What type of better performance are you looking for? Is there a problem with your system?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Mod Squad Bama Rambler's Avatar
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    Re: Am I crazy?

    Even going to 3" on just the manifold probably won't give enough increase in flow to warrant the expense and/or trouble of doing it.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Am I crazy?

    I was hoping to improve a few things.

    - I was wondering if going bigger would solve the cavitation issue.
    - If the pump had extra capacity available to pull more water I was thinking I wouldn't need to leave the second skimmer gate mostly closed (in the picture it's all the way open, but in normal operation I need to keep it around 2/3 closed, making it not all that useful).
    - And then I was thinking that more flow in general would make the pool more efficient in terms of time it takes to filter in a day.

    All seem logical, but I don't have the practical experience to know in advance if this modification would amount to anything worthwhile.

    Thanks!
    Shelley
    Denver, CO

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    Mod Squad Bama Rambler's Avatar
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    Re: Am I crazy?

    I think the best thing you could do is automate the 2nd skimmer valve so it'd stay wide open except when vacuuming.

    If you're having to partially close that valve in order to get enough suction head to run the vacuum then I don't think you're problem is cavitation. What makes you think it's cavitating?
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Am I crazy?

    Thanks Bama. If I run all gates wide open and crank the rpms above 3000 my pump gets pretty noisy and it sounds like pushing gravel. It's worth mentioning that my pump is probably 4 feet above water and, while i've never measured, i don't believe I have much "head" from the return lines. It's not very far and I'm running at a very low PSI on the filter. Though there isn't much point in going above 2750 and I've never had a reason other than the capability exists and I can't use it .

    I suppose I could add another JVA and use it to control both skimmer gates, but ideally I'd like to have a system that will still work if the vacuum hose is accidentally disconnected. Since it's all automated the system could turn on vacuum mode and have no way to pull water from the pool. The pump will turn off automatically if it loses prime... but it's a pain.
    Shelley
    Denver, CO

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    Mod Squad Bama Rambler's Avatar
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    Re: Am I crazy?

    In order to operate that pump at full speed you need every suction you have wide open and I don't think that's enough given the pipe sizes and runs.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Am I crazy?

    You've successfully convinced me that I'm crazy. Thanks Bama .
    Shelley
    Denver, CO

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    Re: Am I crazy?

    I think Bama's idea about automation might make sense. I have a much simpler plumbing setup, but I was having trouble balancing the skimmer vs. vacuum side cleaner. I added an actuator to the 3-way valve that controls the intake from the skimmer vs. vacuum line and connected this to my Easytouch. I program a "Cleaner" item on the schedule to open this valve all the way and to kick the pump speed down to an optimal speed that seems to work well for running the cleaner. The rest of the time, the skimmer operates with this valve closed. It all works quite well. Trying to get things set by optimizing the suction between several intakes seems like an exercise in frustration. Once you get everything dialed in, the filter pressure goes up and your flow rates go down due to needing a backwash. The result is that nothing works right after that. With automation, you are much more likely to get what you want even when the flow rates drop prior to a backwashing session.
    38K in ground pool with attached spa. Current equipment: Easytouch 8 (521150) with IC-60 SWCG with web control by Autelis, 1x Pentair IntelliFlo 011018 pump (for filter), 1x Pentair 2HP WhisperFlo pump (for waterfall), 2X Pentair IntelliBrite 5G 12V lights, Pentair MiniMax400 NG Heater, Pentair SMBW2060 DE filter. Zodiac Barracuda MX8 cleaner on dedicated cleaner line. Lighting/home automation controlled by Insteon/ISY-99i.

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