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Thread: Low Suction Problems

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    Low Suction Problems

    Just put a new motor on my pump and the suction is very low. Went from a .75 HP motor to 1 HP motor. Pump is a RS750CA.

    1) 16,000 gallons
    2) DE Filter
    3) In Ground
    4) Vinyl painted plaster
    5) Hayward RS750CA with a new 1 HP Motor

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    Re: Low Suction Problems

    Welcome to the forum.

    Need more information.

    Is the flow into the pool low? What is the psi on the gauge? Is their air in the pump strainer basket?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Low Suction Problems

    Flow into the pump is low and not filling the basket area of the pump. PSI on the canister is 0. Yes, air in the pump strainer basket. Tried to prime it by dumping a bucket of water in when I started it up but didn't pull it down like it used to.

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    Re: Low Suction Problems

    Yeah, You have a suction side air leak. Somewhere between the pump and the skimmer(s), air is being sucked into the system. Find that leak and your issues will be solved.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Low Suction Problems

    Could it be that I put a 1 HP motor on a pump that says .75 HP / 1.32 SF / .99 THP on it without changing the impeller?

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    Re: Low Suction Problems

    Yeah, that seems logical to me. The bigger pump will "pull" harder making the suction side more susceptible to air leaks.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Mod Squad Bama Rambler's Avatar
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    Re: Low Suction Problems

    As long as the motor sfhp is equal to or greater than the current sfhp (. 99) then it will be fine. The impeller is what regulates the dynamic of the pump so changing the motor doesn't really change anything as long as the speed matches.
    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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