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Thread: Hot Tub Water Level is Dropping

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    Hot Tub Water Level is Dropping

    So I moved into a new house last year with an existing pool and hot tub, so I'm pretty new to this. The hot tub sits above the pool and has a nice waterfall overfill running into the pool. My problem is that whenever I open the inlet valve from the hot tub (pulling water from the hot tub into the pump), the water level will drop to the level of the pool. This happens if the pump is on or off. It doesn't seem to matter where the outlet valve is set. Can someone explain why this is happening and how I can prevent it. Thanks.

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    Join Date
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    Re: Hot Tub Water Level is Dropping

    Please post a picture of the equipment pad.

    Does the water seem to be going back in to the pool or is it lost?

    As I understand what you wrote,it sounds like it's going back into the pool. If the pump is running and you turn the valve that controls return water to the pool or spa to the the spa position and then the suction valve that controls whether water is drawn from the pool or spa to the spa, the water level is dropping. If you turn off the pump, the water level in the spa will continue to drop.

    If this is the case, I would say you have two issues. One is a leaking return flow valve and the the other is a leaking spa return side check valve.

    I'm looking forward to seeing the pix and your response.

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  3. Back To Top    #3

    Re: Hot Tub Water Level is Dropping

    Yes PoolGuyNJ, what you said is correct. As long as the suction valve from the spa is open, then the water will drop. The position of the return valve does not seem to matter. I also believe the water is going back into the pool as the water level of the pool remains the same. So I'm not having to add more water every time the spa water goes down. If the suction valve to the spa is closed, then everything works fine. Something else I noticed is that the filter tank ends up with a lot of air in it when the spa level drops. I think the water level in there is also dropping.

    So if I do have a problem with the valves that you mentioned, what is involved in repairing these?

    Thanks again.
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    JasonLion's Avatar
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    Re: Hot Tub Water Level is Dropping

    If you set the suction side to draw from the spa/hot tub, the spa should drain down unless the suction is set to 100% from the spa, the return valve is set to 100% going back to the spa, and the pool cleaner line is 100% shut off. Have you tried that combination: 100% from spa, 100% to spa, pool cleaner 100% off? When set that way, the equipment pad should be connected only to the spa, and there shouldn't be any way for the spa to drain.

    The "pool cleaner" is the pipe between the two hot tub pipes that goes to a very small secondary filter and then to a valve in the back near the filter. It may or may not actually be connected to a pool cleaner. My guess is that you have that valve in the back set to allow some flow to the pool cleaner, and that is the path that allows the spa to drain.

    There should also be a check valve in the spa return line. I think it is that gray T/90 degree corner near the automated return valve, though I can't be sure from the picture. If that check valve is not working the spa will be able to drain when in pool mode with the pump off.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Hot Tub Water Level is Dropping

    On the spa return line, put a 2" check valve on the vertical pipe. Jandy and Waterway make ones with replaceable spring loaded flappers. Both work well.

    Verify the brand of valves under the actuators. While the handle size and keying is standardized but the insides are not. Jandy, Pentair, and Hayward all make black ones but the gate sections don't fit in each other's bodies. If it says NeverLube, it's Jandy. Pick up a couple of matching valves to what you have. Do them both, suction and return. If one is dead, the other isn't far behind.

    Remove the screws and pop the gate from the body and put them on the existing bodies. The screw sizes used by everyone I have seen is the same thread size. Just remember the long screws for the valve actuator. Also note that the gate sections is the same for each respective brand is the same at 2" as 1.5" but the 1.5" part is likely to be a bit less $$. The 2 port valves are also less $$. Valves are not cheap. MSRP on a 2 way is a bit over $85 but discounted parts are easy to find.

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  6. Back To Top    #6

    Re: Hot Tub Water Level is Dropping

    Thanks for the help everyone. I really thought the check valve was going to be the problem, but it seems to be working. A few notes: the heater has been replaced since the previous photo, taken last summer. The electronic inlet valve died and is now just a mechanical one. I’m not sure if the system was working correctly when I moved in last July or if it just presented itself when I started messing with the valves.

    Anyway, here is what I have done. I did all of this with the pump OFF. My starting point is with the inlet valve closed on the spa side (see photo). When I turn the inlet valve to open the spa intake, I can hear water start flowing. I’m assuming this is the problem I’m having and the water is flowing down into the pool.

    I opened up the end of the check valve and pulled out the spring and assembly. They look fine and do not seem to be stuck. I put the assembly back in and push against it with my fingers and then opened the valve. I still heard water flowing. I thought maybe it wasn’t getting a good seal, so I put plumbers putty around the assembly and around the cap and put everything back together. I still heard water flowing. I removed the putty after this didn’t work.

    Now if I open the valve all the way and close the return valve to the pool (100% from spa and 100% to spa) then the water stops.

    Now I’m stuck. Any thoughts?
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    Mod Squad Bama Rambler's Avatar
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    Re: Hot Tub Water Level is Dropping

    Coming to this party late here's what I believe is happening and from Jason's post he had it right from the beginning. There is no check valve in the pool suction line (pool line going into the pump suction). Since the spa is higher than the pool any time the suction valve is drawing from both spa and pool, water will flow backward in the pool suction line and drain the spa. This will happen to some extent whether the pump is running or not. IMO there is not a problem with the system. This is exactly how it's designed to operate.

    There are two ways to overcome this.
    1) Always run the system either 100% spa or 100% pool.
    2) Add a check valve in the pool side suction line with flow toward the suction valve. This will prevent water from flowing back to the pool from the spa. The only caveat to this is that if you ever "wanted" to drain water from the spa back to the pool you couldn't. You could still pump water from the spa back to the pool however.
    Dave J. TFP Moderator
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    Re: Hot Tub Water Level is Dropping

    If your spa spills into the pool:

    When circulating in the normal pool mode, the suction should come exclusively from the pool. The return line should be slightly open to the spa but sending the majority of the return flow to the pool. The spa will fill and spill over into the pool. This skims the surface and ensures freshly chlorinated water is always getting in the spa.

    When the pump is off, the check valve will prevent the water in the spa from siphoning to the pool through the returns.

    If it doesn't, the water will lower in the spa to the returns' level or the water level in the pool, whichever is higher.
    If the spa drains the the lower of the two, the suction side valve is leaking. It's possible for both the return side check valve and drain valve to be leaking.

    As Jason said, only use the pool sweep in pool mode or you will drain the spa.

    Spa mode is defined as all suction from the spa and all return water to the spa.

    Trying to run both bodies of water at the same time is next to impossible. The spa will either overflow or drain every time.

    If your spa is not a spill over and doesn't have any way to prevent overflows, the spa must be run daily for an hour or two (split cycles are OK) so it gets circulation and chlorine. The valves for the suction and return must be 100% for each.

    If the spa has overflow protection, depending on the capacity to draw excess water, it may be treated as a spillover or as a stand alone. I usually treat them as a stand alone body of water since the capacity to drain the overflow is usually fairly low.


    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  9. Back To Top    #9

    Re: Hot Tub Water Level is Dropping

    Thanks everyone. This does makes sense even if I don't really like it. It sounds like everything is actually working correctly. I will just make sure the valves are in the correct position when running in spa mode and hopefully I won't drain it again.

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