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Thread: Proper Location of Autofill on Infinity Pool Question

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    Proper Location of Autofill on Infinity Pool Question

    We're on the last leg of building an infinity pool, and the PB has placed the autofill on the main pool and not the basin. During the calibration and turning of all the pumps, the water in the basin overflowed to the hill side below. The PB is coming back tomorrow to "adjust" the system. From what I read so far, placing the autofill on the main pool is a no no, and this needs to be on the basin instead?

    Any input would be greatly appreciated.

    TIA

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    JasonLion's Avatar
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    Re: Proper Location of Autofill on Infinity Pool Question

    The autofill should be on the catch basin for reliable operation. Maintaining a proper minimum water level in the catch basin is important for the operation of the edge pump and can not be reliably determined from measuring the pool. Putting the auto-fill on the pool can result in the edge pump losing prime, which can potentially damage the pump (which is, however, extremely unlikely if you run the edge pump regularly).

    The whole situation is fairly complex, with a couple of different failure modes, so there are other approaches, including auto-fill at both levels, or more complex electronic systems with multiple water level sensors (which aren't all that common, but nice to have). The main advantage of the more complex systems are to control overflow during heavy rain and to compensate for high evaporation rates coupled with infrequent use of the edge pump.

    The overflow you describe is probably a simple mis-calibration of your current fill system, though it is remotely possible that it is indicative of some more complex problem. I don't see a way it could be the result of the incorrect placement of the auto-fill system, which would have very different symptoms.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Proper Location of Autofill on Infinity Pool Question

    Always, always, always install the autofill on the catch basin. If your pool builder has it located up on the main pool, I would question everything in their hydraulic design.

    Please read this article by well respected designer Scott Cohen. I've met him and attended his educational seminars. Part of his professional time is spent as an expert witness on lawsuits against builders like yours that ignore common knowledge in the trade.

    Vanishing Edge Problems and Solutions

    The key part of the article that applies to your situation:

    "A few years back, for example, I saw a pool where the auto-fill leveling device had been installed on the upper level of the system, on the pool itself, where it was utterly worthless. Instead, the leveling system needs to be in the catch basin, where itís actually possible to tell if more water is needed. You simply canít determine that need up on top, where the edge itself and the flow over it obviously define the precise level of the pool."


    Steve
    APSP Certified Building Professional
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    NSPF Certified Pool Operator

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    Re: Proper Location of Autofill on Infinity Pool Question

    Quote Originally Posted by JasonLion View Post
    The autofill should be on the catch basin for reliable operation. Maintaining a proper minimum water level in the catch basin is important for the operation of the edge pump and can not be reliably determined from measuring the pool. Putting the auto-fill on the pool can result in the edge pump losing prime, which can potentially damage the pump (which is, however, extremely unlikely if you run the edge pump regularly).

    The whole situation is fairly complex, with a couple of different failure modes, so there are other approaches, including auto-fill at both levels, or more complex electronic systems with multiple water level sensors (which aren't all that common, but nice to have). The main advantage of the more complex systems are to control overflow during heavy rain and to compensate for high evaporation rates coupled with infrequent use of the edge pump.

    The overflow you describe is probably a simple mis-calibration of your current fill system, though it is remotely possible that it is indicative of some more complex problem. I don't see a way it could be the result of the incorrect placement of the auto-fill system, which would have very different symptoms.
    Jason, thank you for your input. Are you suggesting that it is OK or standard industry to place the autofill at the main pool instead of the basin?


    Quote Originally Posted by poolkid
    Re: Proper Location of Autofill on Infinity Pool Question
    Always, always, always install the autofill on the catch basin. If your pool builder has it located up on the main pool, I would question everything in their hydraulic design.

    Please read this article by well respected designer Scott Cohen. I've met him and attended his educational seminars. Part of his professional time is spent as an expert witness on lawsuits against builders like yours that ignore common knowledge in the trade.

    Vanishing Edge Problems and Solutions

    The key part of the article that applies to your situation:

    "A few years back, for example, I saw a pool where the auto-fill leveling device had been installed on the upper level of the system, on the pool itself, where it was utterly worthless. Instead, the leveling system needs to be in the catch basin, where itís actually possible to tell if more water is needed. You simply canít determine that need up on top, where the edge itself and the flow over it obviously define the precise level of the pool."


    Steve
    Steve, thanks for the link, that's the same article that I read regarding placing the autofill on the main pool is a no no in the industry. I would hope PB will come to his sense and place the autofill over to the basin, How difficult is it for PB to rectify his mistake and place the autofill on the basin side?

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    Re: Proper Location of Autofill on Infinity Pool Question

    As Jason mentioned, it can be very complex. You of course have to have a live water line. The choice of autofill type and location partially depends on the type of basin. A shallow but large surface area basin may allow a normal pool style autofill, where a deep small surface area basin may need a specialized unit made specifically for the task. Electronic versions are more expensive, but have great flexibility.

    With a mistake like this, I'd also be very concerned about basin size in relationship to the pool, plus the layout of the pumps and plumbing. Overflowing the basin during start up is a red flag. Well designed vanishing edge pools are built so that can't happen. Ever.

    Depending on where you're located, I could potentially set you up with an industry expert to assess what you've got.
    APSP Certified Building Professional
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    Re: Proper Location of Autofill on Infinity Pool Question

    Quote Originally Posted by poolkid View Post
    As Jason mentioned, it can be very complex. You of course have to have a live water line. The choice of autofill type and location partially depends on the type of basin. A shallow but large surface area basin may allow a normal pool style autofill, where a deep small surface area basin may need a specialized unit made specifically for the task. Electronic versions are more expensive, but have great flexibility.

    With a mistake like this, I'd also be very concerned about basin size in relationship to the pool, plus the layout of the pumps and plumbing. Overflowing the basin during start up is a red flag. Well designed vanishing edge pools are built so that can't happen. Ever.

    Depending on where you're located, I could potentially set you up with an industry expert to assess what you've got.
    I'm in Houston TX, if you know of an expert in this area please PM me.

    Earlier today I started the gushers (4 bubblers & 1 sheer decent of 4 ft) and the surge spilled over to the basin causing it to overflow and flood the below hill once again. I called the PB and he said that I must first turn on the edge pumps before turning on the gushers ... does this sound right? I've informed him about the location of the autofill needs to be on the basin and not the main pool and he went into defensive mode vehemently argued with me otherwise.

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    JasonLion's Avatar
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    Re: Proper Location of Autofill on Infinity Pool Question

    There should always be an auto-fill on the lower basin to protect the edge pump. There can optionally, in addition, be one on the main pool. There are also more complex systems with electronic sensors (at least one of which will be on the lower basin). Regardless, the lack of a lower auto-fill would not have caused the overflow you mentioned.

    I also have concerns about the builder based on your comments. However we don't really have enough information here to say that it is time to call in outside experts just yet, though it may come to that. For example, perhaps there actually is a lower auto-fill in addition to the upper auto-fill? For the moment I am leaning towards seeing if the builder can make it right for a little while.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Proper Location of Autofill on Infinity Pool Question

    PB explained to me today that there is an autofill on the basin as well as on the main pool. This pretty much alleviated my most concerned issue

    How can I verify that the autofill is installed in the basin?

    PB is waiting for the Pentair tech to come later this week to make final adjustment and calibrate the equipment. Aside from the questions I have regarding the hydraulic system; overall, the PB did a great job, this is the second pool he built for me, the last one was over 2 years ago but was not an infinity pool. I will post pic of the pool once the Pentair guy completed the calibration.

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