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Thread: Low Flow

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    Low Flow

    I've now had 2 pool company guys, a plumber, and several friends try to diagnosis and fix my pool flow problem. All of them say "this is really strange" but none of them have fixed the problem. The plumber said he would come back and start taking things apart, but it would be pricey. The pool guys have suggested it could be: bad header in the heater obstructing flow, something stuck in the drain or skimmer lines, or HP too low on the pump. Here's the deal: The pool primes, the pump runs, but the return flow is terrible as is the suction at the skimmer and drain (almost non-existent). BUT, when I turn the first valve after the output (red valve below), water comes gushing out with a lot of power and the pump starts flying and skimmer sucking etc.

    I'm wondering if the water flow is indeed being obstructed at the heater OR maybe that check valve in the middle? Should I put in a bypass around the heater and see how things go? Any advice?

    THANKS
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    In ground Fiberglass pool 11000 gal. (42000 liters)
    Cartridge filter, Hayward C3025 (122GPM)
    1.5 hp pump, 2in piping
    Hayward Goldline PL-P4 salt water pool system and automation
    http://fibro.ca/html-ang/25-PIS-fiche.php?numero=16

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    Mod Squad JohnT's Avatar
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    Re: Low Flow

    Welcome to TFP!

    From what I can see, that valve sends water someplace besides through the heater and chlorinator. Where does it go? Does the flow increase when you open it or close it?

    I'd be upgrading that check valve too. Get a big one that has full flow when it's open.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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    Re: Low Flow

    Where does the red valve go? just an open pipe for draining?
    If so, then yes you have a blockage somewhere- you can try loosening the union on the outlet side of the heater and see if you get the same water flow or not- that will tell you if the clog is in the heater or somewhere downstream...
    24ft x 52in AGP 18000 gal
    sand filter, 200#,1.5 hp single speed pump
    Wood deck (still in progress...)

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    Re: Low Flow

    Wow...you guys are fast...thank you. The red valve opens to nothing...just a drain (very powerful when opened). I hooked up a hose to it yesterday so that I could leave it opened and the pump, flow, and suction all increased significantly.

    I'm not sure that I understand how to loosen the union at the outlet side of the heater. Just unscrew it?
    In ground Fiberglass pool 11000 gal. (42000 liters)
    Cartridge filter, Hayward C3025 (122GPM)
    1.5 hp pump, 2in piping
    Hayward Goldline PL-P4 salt water pool system and automation
    http://fibro.ca/html-ang/25-PIS-fiche.php?numero=16

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    Mod Squad JohnT's Avatar
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    Re: Low Flow

    Quote Originally Posted by pachito

    I'm not sure that I understand how to loosen the union at the outlet side of the heater. Just unscrew it?
    Yes, unscrew it. You may need a strap wrench or Channel-Locks to open it.

    I'd take the inlet side off as well to test the flow through the check valve if removing the outlet fitting doesn't result in better suction at the skimmer.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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    Re: Low Flow

    In the meantime, the hose you hooked up to the red valve can be dumped in the pool- that way your filter will be online and getting some circulation!
    Also, this means you don't have any apparent problems on the suction side!
    24ft x 52in AGP 18000 gal
    sand filter, 200#,1.5 hp single speed pump
    Wood deck (still in progress...)

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    Re: Low Flow

    Thanks. Any recommendations on type of check valve to replace that one with?
    In ground Fiberglass pool 11000 gal. (42000 liters)
    Cartridge filter, Hayward C3025 (122GPM)
    1.5 hp pump, 2in piping
    Hayward Goldline PL-P4 salt water pool system and automation
    http://fibro.ca/html-ang/25-PIS-fiche.php?numero=16

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    Re: Low Flow

    1st check the heater- if you open the outlet union and no flow, check the inlet side. if you get good flow from the outlet, then check the valve... if no flow from heater but good flow from heater inlet, then the problem is in the heater and the valve is probably fine!
    24ft x 52in AGP 18000 gal
    sand filter, 200#,1.5 hp single speed pump
    Wood deck (still in progress...)

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    Mod Squad JohnT's Avatar
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    Re: Low Flow

    Quote Originally Posted by pachito
    Thanks. Any recommendations on type of check valve to replace that one with?
    Jandy http://www.zodiacpoolsystems.com/Pro...eck-Valve.aspx
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  10. Back To Top    #10

    Re: Low Flow

    Great. I'm going to try all of this in the next few hours and see what I find out. After just looking at everything again, I realized I also have a check valve right before the chlorinator...another possible culprit I guess. That one won't be as easy to check, I don't think, so I hope I find the problem before it.

    Another question: I have an Aquabot cleaner with a bad track belt. Do you guys recommend any particular pool company to order a replacement belt from?

    Thanks again.
    In ground Fiberglass pool 11000 gal. (42000 liters)
    Cartridge filter, Hayward C3025 (122GPM)
    1.5 hp pump, 2in piping
    Hayward Goldline PL-P4 salt water pool system and automation
    http://fibro.ca/html-ang/25-PIS-fiche.php?numero=16

  11. Back To Top    #11

    Re: Low Flow

    Bad news: Heater seems fine and all check valves seem fine. When we opened the union to the return line, we had a lot of pressure and water. The thing is, the return line goes downhill, so there really shouldn't be much or any water there. We tried to blow out the return line and barely got any air going through. Looks like I am going to get a roto-rooter company out here next...
    In ground Fiberglass pool 11000 gal. (42000 liters)
    Cartridge filter, Hayward C3025 (122GPM)
    1.5 hp pump, 2in piping
    Hayward Goldline PL-P4 salt water pool system and automation
    http://fibro.ca/html-ang/25-PIS-fiche.php?numero=16

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    tsunami's Avatar
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    Re: Low Flow

    Has the outlet flow always been weak?
    40 X 26 Free Form Pool with attached 9 X 7 Spa raised 18" with 8 Jets and Spillover, and an Art Rock Waterfall/Grotto with accent rocks, 26,000 gallons
    Intelliflo VF-3050 for Pool, VS-3050 for Spa Jets, VS-3050 for Waterfall/Grotto, Quad DE 80, 400K BTU Mastertemp, Intellitouch i7+3 w/ iS10 10 Function Spa-Side Remote, Intellichlor IC40 Salt Chlorinator, Telephone Remote, 2 Intellibrites for Pool/ 1 for Spa, Solar Panels on 2 story Roof w/ 75% coverage
    Pebble Tec Tropical Breeze Tsunami's Pool Build

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    Re: Low Flow

    I just bought the house last year and I'm a first time pool owner. I was told half-way thru the pool season that my suction/output was bad. I spent the remainder of the season trying to figure out what was wrong and the pool guy said "we'll take care of it next year." This year it's even worse...barely any output and the pressure gauge reads 40psi. Today we checked everywhere and it looks like the problem is in the return.

    Tomorrow I have a new pool company coming out. In the meantime, I hooked up a hose to bypass everything except the filter and the pump is going great (18psi) with the hose gushing the water into the pool with force and the skimmer and main drain finally working like they should. I fear the pool people are going to have bad news for me tomorrow.
    In ground Fiberglass pool 11000 gal. (42000 liters)
    Cartridge filter, Hayward C3025 (122GPM)
    1.5 hp pump, 2in piping
    Hayward Goldline PL-P4 salt water pool system and automation
    http://fibro.ca/html-ang/25-PIS-fiche.php?numero=16

  14. Back To Top    #14
    Mod Squad JohnT's Avatar
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    Re: Low Flow

    The obvious place for something like a pump drain plug to have gotten stuck is the water pickup for the chlorinator. It sticks down into the pipe and wouldn't let anything large past it. If you don't mind working with PVC, cut the line so you can see through the pipe below the chlorinator. 15 minutes could save you a service call.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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