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Thread: Pool Raised Spa Plumbing Question

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    Pool Raised Spa Plumbing Question

    I have a new pool with a raised spa with an overflow. Now that it is winter I want to run without the overflow on. The problem is that when the valve turns from spa to pool mode water drains from the spa drain to the pool (clearly because the relative height of the spa drain). Without the overflow on each time the valve goes from spa to pool more water is drained until the spa is empty. This means I cannot have the system in freeze protect without the overflow on. Surely there is a fix for this? Thanks for any help.

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    mas985's Avatar
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    Re: Pool Raised Spa Plumbing Question

    Yes, there is a fix. You will need a check valve on both the suction and return spa lines.

    But for general cleaning, I normally use overflow mode rather than spa only mode. The reason is that any debris on the surface can only be removed in overflow mode. Also, if the spa is used a lot, you are better off replacing the spa water with pool water.

    But I don't understand how that relates to freeze protection. Most controllers will cycle through the various modes when freeze protection is on.
    Mark
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    BoDarville's Avatar
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    Re: Pool Raised Spa Plumbing Question

    Welcome to TFP!

    The first thing I would investigate is the check valve that should be located in the plumbing lines to the spa. The check valve is not a user-adjustable flow control valve. Its purpose is to prevent water from flowing backward from it's normal flow direction. It's common pool/spa use is to keep the spa from draining back into the pool when the pump is off or when the water flow to the spa is turned off (e.g., turning the overflow off).

    Another thought...Since the water was drained from the spa with the pump running, you could also do have a damaged diverter inside the suction side valve.
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    Re: Pool Raised Spa Plumbing Question

    Thanks for the reply(s). The problem occurs (I think) when the pump is off and the automatic valve is moving from spa to pool. There is no check valve on the suction line, so maybe that's the problem. I normally run overflow because I agree that cleaning and water chemistry is easier that way. My freeze protect runs the pool for an hour, and then it switches over to spa for an hour. Without overflow on the spa loses 5-8" of water each time until its empty. The reason I don't want to run overflow all of the time is that my pool temp is now 45 degrees (in OKC) and there are many night/mornings nice enough to use the spa, and I'd rather not have to heat it back up from 45 every time.

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    mas985's Avatar
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    Re: Pool Raised Spa Plumbing Question

    I bet you will use less energy heating it up from 45 than keeping hot all the time but that is up to you.

    You probably just need to install some check valves. They are normally installed for a raised spa and since this is a new pool, you should get your PB to add them.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Pool Raised Spa Plumbing Question

    Thanks again for the reply and warm welcome. I don't necessarily want to run the heat on the spa all night, but on those Saturday night Sunday morning combos I think the spa temp won't go down more than 30-40 degrees. It sounds like I need a check valve on the suction line, but I'm a little concept confused- a check valve is supposed to keep water from flowing the wrong way. In this case we appear to be losing water that is flowing the right way at the wrong time. Won't a check valve interrupt normal operation of the suction line? By the way I read the rules and will fix my sig tomorrow. Thanks again!!

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    mas985's Avatar
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    Re: Pool Raised Spa Plumbing Question

    The check valve on the spa suction pipe will prevent draining when the valves are in spillover mode and the pump is shut off. However, it will not stop any flow while the valves are in transition.

    However, you can put a check valve on the pool suction pipe and that will prevent the spa suction side draining into the pool suction side while in transition.

    A check valve on the return side spa pipe will also prevent back flow when in spillover mode and the pump is shut off. But it will also help with the valves in transition on that side.

    So putting a check valve on both the pool suction pipe and spa return pipes should solve the problem.


    But I re-read your first post and I have a question about this:

    Without the overflow on each time the valve goes from spa to pool more water is drained until the spa is empty.
    This should not normally happen. If some water drains from the spa to the pool, it should stop at the pool level. Has this actually happened where the spa is completely empty? How high is the spa relative to the pool?
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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