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Thread: Vacuum breaker sucking air after new pump install. Do I need a stronger pump?

  1. Back To Top    #1

    Join Date
    Jun 2016

    Vacuum breaker sucking air after new pump install. Do I need a stronger pump?

    Hi All,

    I recently installed a 1.5hp Hayward SP2303VSP variable speed pump to replace my old Pentair WFE-6 1.5hp single speed pool pump. I didn't realize it at the time but while the HP rating is similar, the flow curve of the old pump shows that it was a much stronger pump. After installation, I don't get any bubbles in the discharge until I turn on the solar panels on my second story roof. On the highest RPM of the pump, after the initial clearing of the panels, I continue to get bubbles in the outtake. On the roof, I can hear the breaker valve sucking air. I guess I don't have enough pressure to close it. Here are my options as far as I can tell but I'd appreciate any advice you can offer.

    1. Install a stronger pump. I can still return the Hayward SP2303VSP I installed and get something stronger. On the highest setting, the new Hayward doesn't seem to have any problem getting water to the roof or motivate the suction cleaner. The pressure on the filter isn't as high as it used to be but as far as the function of the filter, it seems to be working fine other than not closing the vacuum breaker.

    2. Replace the vacuum breaker. I don't know, maybe a new one will close with less pressure?

    3. Move the vacuum breaker location. It's currently at the very highest point of the panels. I could move it to a T connector right in front of the first header so the resistance is downstream of the valve.

    4. Ignore the bubbles. Can I safely ignore the leak or do I need to fix this?

    If you were in my situation, what would you do? Thanks for any and all advice!


  2. Back To Top    #2
    needsajet's Avatar
    Join Date
    Jan 2016
    Sydney, NSW, Australia

    Re: Vacuum breaker sucking air after new pump install. Do I need a stronger pump?

    Is all your flow currently going to the solar heating system when it operates? If that's the case, I'd look for a higher flow pump so you still get all the heat you can.

    Otherwise, it should be controlled by a three-way valve, then adjust the stop on the three-way valve to send more water to the solar panel side, allowing less flow to go directly back to the pool.

    If it's controlled by a two-way valve, and has this problem when that valve is fully open, then look for how they throttled the bypass to force water to the panels. If the two-way valve is only partially opening, then you could adjust the stop so that it opens more and see if that's enough to pressurize the vacuum relief valve, and/or throttle the bypass more.

    I've read, but have never seen, that you can put use a valve to throttle the return line from the panels, but that would reduce the heating capacity.

    The vacuum relief valve should stay at the highest point to be sure of proper draining, though I can think of some layouts that would still drain OK.

    Eliminating air in the system helps it function quietly as well as eliminating the bubbles, and also minimizes electricity for pumping and reduces wear. There may be other problems I can't think of, but if it were mine I'd get it sorted out so there's no air being pulled in while operating.
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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