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Thread: suction and return dwindle to no flow.....

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    suction and return dwindle to no flow.....

    i was told by the tech that replaced the pump and filter to my pool that i possibly have a suction side leak causing a no flow situation after the filter. i by passed the suction side plumbling with 2inch pvc directly from the pump to the pool and i am getting the same results. ok suction starts out strong and the flow through the filter to the return is strong initially but dwindles down to nothing after about 15 minutes. i have a haward pump and de filter and a larger approximately 30 by 20 pool. any suggestions as to how to diagnose this problem

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    Texas Splash's Avatar
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    Re: suction and return dwindle to no flow.....

    Hello and welcome to TFP! So if you have gone so far as to experiment and run a straight pipe from the water directly to the pump inlet, we can only assume the pump's strainer basket is full of water correct? No difficulty in priming and staying full? If that's the case, then there should be no suction side leak issues. The issue then becomes focused on the water flow from the pump to the filter and beyond. Some things to consider:
    - Is that new pump operating properly? (Perhaps problems internally)
    - Is the filter itself getting clogged? Possibly over-charged with DE?
    - What is your filter pressure and how does the filter gauge respond after it has ran for a while?
    - Finally, what is the condition of the water itself? Cloudy, tinted, any chance there's algae in there? Do you have any test results you could provide?

    These are just some preliminary items I could think of. Others may have other suggestions or questions based on your reply as well. Hopefully we can help get your issue resolved soon.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
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    Re: suction and return dwindle to no flow.....

    Have you tried to back flush your piping with a garden hose. Is the impeller clear. Have you back flushed your filter recently. What are the pressure gauge values during your run.
    In ground, 14,000 gallon, white plaster, unheated, stone waterfall, DE Filter, Rainbow 320 Cl, Polaris 3900, FloVis flow meter, F100 test kit, Circupool RJ30+ SWG, Circupool VJ1/Speck Badu EcoM3V variable speed pump.

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    Richard320's Avatar
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    Re: suction and return dwindle to no flow.....

    Welcome!

    Pressure changes on the filter gauge will tell a lot. Low flow/low pressure is problem on the suction side. low flow/high pressure is a problem after the pump. If your pool is green, what you describe is a filter getting loaded up. What happens after a backwash and recharge?
    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: suction and return dwindle to no flow.....

    Pump running, is there air in the pump strainer basket? (with the new 2" pipe you put in)
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: suction and return dwindle to no flow.....

    Quote Originally Posted by duraleigh View Post
    Pump running, is there air in the pump strainer basket? (with the new 2" pipe you put in)
    Pressure settles at 23. There is a small bubble at the top of the lid. Soon after starting it maintains prime and appears to be moving through the filter but checking there is no flow????? Chking suction it also dwindles down to little to no suction but the pressure gauge shiows 23????? It is doing the same as before I rerouted the suction line... I don't know how to attach pics???!

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    Texas Splash's Avatar
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    Re: suction and return dwindle to no flow.....

    Have you tried linking your photos from Photobucket? That's what many of us do here on TFP. Upload your pics to Photobucket (free), then copy & paste the IMG code for that pic from Photobucket to your TFP post. Works great.

    Also, you can try going to the bottom of your quick reply post where it says “Go Advanced”, and then down to where it says “Manage Attachments”. It may let you upload them that way. They may show-up large because you can't adjust the size of the attachment, but it may work.

    As for the water flow ..... you should have an air relief valve at the top of your DE filter. You can open it a little while running to expel air quickly followed by water which will tell you water is indeed flowing into the filter from the pump. How about the backwash questions in post 3 & 4? Any history on those maintenance actions performed, or anything odd noticed during them?
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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    Re: suction and return dwindle to no flow.....

    Your pump will develop pressure even with no flow.

    check your chemistry and open up your filter.
    In ground, 14,000 gallon, white plaster, unheated, stone waterfall, DE Filter, Rainbow 320 Cl, Polaris 3900, FloVis flow meter, F100 test kit, Circupool RJ30+ SWG, Circupool VJ1/Speck Badu EcoM3V variable speed pump.

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    Re: suction and return dwindle to no flow.....

    Quote Originally Posted by WASP View Post
    Your pump will develop pressure even with no flow.

    check your chemistry and open up your filter.
    I have good flow through the relief valve and it feels like I'm getting flow through the exit pipes but no flow out of the returns???
    If I turn off the pump I initially get good flow and then it diminishes after 10 minutes. When u back flush it works great and when I hook up the sweeper on back flush it zips around but gradually loses its movement...all the while I'm getting 23 at the gauge and pump is pumping but no suction or return flue???

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    Texas Splash's Avatar
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    Re: suction and return dwindle to no flow.....

    Based on those indications, I think we're back to two things that should be confirmed:
    1 - Full set of test results ( to ensure your filter isn't struggling with excessive organic materials)
    2 - Tear-down/cleaning of filter (to see your grids, manifolds, or pipes have excess accumulation of DE or gunk that cannot simply be backwashed)
    Unless someone has another idea based on all the symptoms, that's what comes to my mind.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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    Re: suction and return dwindle to no flow.....

    Quote Originally Posted by Texas Splash View Post
    Based on those indications, I think we're back to two things that should be confirmed:
    1 - Full set of test results ( to ensure your filter isn't struggling with excessive organic materials)
    2 - Tear-down/cleaning of filter (to see your grids, manifolds, or pipes have excess accumulation of DE or gunk that cannot simply be backwashed)
    Unless someone has another idea based on all the symptoms, that's what comes to my mind.
    Looks like I got to open that filter and see for myself... Pool tech was just out 3 4 days ago new filter in January and he says filter is good??? Don't want to void any warranties but If I must I'm going to open it up... But what gets me is if I run the hose back through the returns I get excellent flow but for only 15 minutes?????

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    Re: suction and return dwindle to no flow.....

    But what gets me is if I run the hose back through the returns I get excellent flow but for only 15 minutes?????
    I don't understand....what hose goes "back through the returns".

    YOur description of the symptoms is hard to figure our but my bet is you have algae in your pool that you can't see but that is clogging your filter.

    Can you post a set of test results?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: suction and return dwindle to no flow.....

    yep pool is green...no flow from filter to pool. the pump is working and the water comes out of the filter pressure release on top of the filter but it does not flow water out of the pressure side returns. i am able to get the flow going by putting the garden hose into the pressure side return and backflowing water to the filter. it then works good for about 10 minutes and dwindles down to no flow to the pool.

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    Texas Splash's Avatar
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    Re: suction and return dwindle to no flow.....

    Your pics tell the story ... algae. It's amazing how fast algae will be collected and clog a filter. I don't recall you saying earlier, but if you don't have a TF-100 (XL option) test kit, you need one now and need to "SLAM" your pool (link below). That's how to clear your water and help give that filter some relief. The filter will never remove the green, that's only done with proper chlorination. Consider ordering that TF-100 right away and read the SLAM page very carefully before you begin. Let us know if you still have any questions.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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