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Thread: PSI drop w/ temperature drop in 12hr new plumbing test?

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    PSI drop w/ temperature drop in 12hr new plumbing test?

    Hi Everyone,

    We are remolding our pool with new plumbing, coping, plaster and deck.

    Currently, the new plumbing is being pressured tested using water at 30psi to start.

    Last reading taken about 7pm last nite is 30psi with temperature around 75 to 80 degree.

    This morning's reading taken about 7am is 28psi with temperature around 65 to 70 degree.

    Is it safe to attribute the 2psi drop from the temperature fluctuation with this 12hour period?

    Since this is new plumbing, can we run air pressure test with shorter duration to double check?

    Thank you for your suggestion!!

  2. Back To Top    #2
    Mod Squad Bama Rambler's Avatar
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    Re: PSI drop w/ temperature drop in 12hr new plumbing test?

    Welcome to TFP.

    2 psi is easily attributable to the temp fluctuation because there's virtually no way to get every ounce of air out of the system. I'd hold it during the day today and if the sun comes out the pressure should rise back accordingly.
    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
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    JasonLion's Avatar
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    Re: PSI drop w/ temperature drop in 12hr new plumbing test?

    Welcome to TFP!

    You are best off leaving it as is until the temperature warms up today to match yesterday's temperature and then see where you are.

    Water is much better than air, which varies all over the place as the temperature changes.
    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: PSI drop w/ temperature drop in 12hr new plumbing test?

    Hi Dave and Jason,

    Thank you for the quick inputs!

    Since our weather report is forecasting much the same temperature today as yesterday, should I assume it will go back up to 30psi, or close to it?

    Thank you again!!

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    Mod Squad Bama Rambler's Avatar
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    Re: PSI drop w/ temperature drop in 12hr new plumbing test?

    It should get very close to 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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    Richard320's Avatar
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    Re: PSI drop w/ temperature drop in 12hr new plumbing test?

    That's why AC systems are tested with vacuum instead of pressure. Nothing doesn't change with temperature.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: PSI drop w/ temperature drop in 12hr new plumbing test?

    Hi Richard,

    I live not too far from you so as you can see there is not much day to day variation in the weather pattern lately.

    Since it was set at 30psi at around noon yesterday, dropped to 28 this morning, does logic follow that it should go back up to 30psi or close it at some point?

    Following your thought on A/C testing using vacuum, is there an effective way to perform a vacuum test on this plumbing?

    Thank you!


    KC
    Doing my best to avoid the four letter word: "LxxK"

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    Richard320's Avatar
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    Re: PSI drop w/ temperature drop in 12hr new plumbing test?

    Quote Originally Posted by aceropen
    Hi Richard,

    I live not too far from you so as you can see there is not much day to day variation in the weather pattern lately.

    Since it was set at 30psi at around noon yesterday, dropped to 28 this morning, does logic follow that it should go back up to 30psi or close it at some point?

    Following your thought on A/C testing using vacuum, is there an effective way to perform a vacuum test on this plumbing?

    Thank you!


    KC
    Doing my best to avoid the four letter word: "LxxK"
    Yes, it should go back up. As temperature rises, so does pressure. I'm unaware of any way to connect a vacuum system to pool plumbing - it was just a point of interest because your dilemma is not unique.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: PSI drop w/ temperature drop in 12hr new plumbing test?

    Hi Everyone,

    I wanted to report back the PSI readings from the pressure testing using water did fluctuate in sync with the temperature variance during this 36hr period. There was a consistency to the pattern.

    I want to thank everyone for their inputs in help us!!

    KC

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