Do I need a check valve added so my spa doesn't drain?

[Tfastle]

Our 9 year old pool has a hot tub connected to it that's water surface is about 18" higher than the pool's. They share a pump. When not used the water in the hot tub has always slowly gone down. Each year it got progressively worse. About 4 years ago I replaced the diverter inside the Jandy 3 way valve. This helped a great deal but didn't completely fix it. After that repair the rate that the water level dropped in the hot tub returned to roughly the same rate as it was when the pool was was new. Now, 4 years later, the level is dropping much more quickly again - about 12" a week - and I have to fill the hot tub frequently.

I talked with Jandy support and they said that their 3 way valve is not a positive seal and, with an elevated hot tub, there will be some seeping. So, I did some reading on it came to the conclusion that, because my spa is elevated, the builder should have put a check valve on the pool side of the 3 way valve that selects whether the water going into the pump comes from the pool or from the spa.

My plan is to plumb a Jandy check valve (with the spring loaded swing) on the pool side of the 3 way valve which, I believe, should fix my problem of water seeping past the diverter and back into the pool. I have attached a drawing of what I have now and where I am planning to add the check valve is.

While, I fix most things myself I am not a pool professional. So, my questions are:
Is my thinking correct, should there be a check valve where I am considering adding this one?
If I were to ad the check valve might it impact the priming pool pump?
Is the Jandy check valve I am considering the right choice or is there a better check valve option (ball or other)?
Or, should I be going about this in a different manner or, even just live with it?

I think my drawing is fairly clear - one on top is what I have, the one below is the same except shows where I plan to add the check valve. I only included the pertinent portions of the plumbing. The two lines I labeled "skimmer and drain" are from the pool. The return from the spa drain is the single line.

Thanks in Advance for any and all input (in the winter, my family doesn't like having to fill the hot tub before using it ) )

 

[Cymetrix]

With the suction and return line 3-ways in spa mode you shouldn’t have an issue. My guess is you have a bad check valve on the return side that is allowing water to backflow through a spa return line. Does you spa spill over into your pool when in pool mode?

 

[Jimrahbe]

T,

I assume your spa spills over into your pool... If so, that check valve has to be in the line that causes this spillover.

It depends on how your plumbing is set up...

When in the pool mode, is your Return valve set to fully shut off any water going to the spa, or is it offset to allow some water to always go to your spa, even when in the Pool mode???

The problem is on the Return side, and you are trying to put a check valve on the Suction side...

Show us some actual pics of your equipment pad...

Thanks,

Jim R.

 

[Tfastle]

Thanks for the reply.

When the hot tub is heated or the system is in "spa mode" no water goes over the spillway. In service mode I can set the valves to "fill" which pulls water from the pool (skimmer and drains) and returns it to the hot tub but only really do that to fill the hot tub and not for the waterfall. We have a separate water feature with 2 water falls.

We don't have it in spa mode for long periods of time (maybe 2 -6 hours) and have not noticed the water level drop then. The problem is in pool mode and, I think, mostly when the pump is off.
I don't think it's a spa return line issue because, if I don't fill the hot tub, it will drop to a level below all of the return inlets with just the spa drains under water. I also don't think there are any check valves on any of the return lines. I'll check that tomorrow and look at that as a possibility (the return lines) but I'm pretty sure the only current check valve is on the suction side of the pump.

I was thinking it was likely the spa drain because that is where the greatest pressure would be (with the pump off) and it has to have enough to push by the diverter in a 3 way.

With an elevated hot tub is it common practice to put check valves on the suction lines (like my drawing) and the return lines or just one or the other or none?

 

[wireform]

Let's get some pictures of the equipment pad from various angles to assist you better.

 

[Tfastle]

Thanks for the reply Jimrahbe. When in pool mode the return valve is set to fully close. When in Spa Mode the pump is fully diverted (3 ways are closed to the pool) to the spa - sucks from the spa drains, returns via the spa return lines. My thinking was that, with the pump off, the water in the spa was higher than the 3 ways and it seeping back through the suction line and by the 3 way at the pump into the pool suction lines. I have not given a lot of thought to it going out the return lines but will look at it with that in mind as well. I guess, with the pump off, it could actually be either. In my response above to Cymetrix's reply I said that I thought the water level in the tub was below all of the return lines but that is wrong. I forgot there are two return lines near the bottom of the hot tub that are still underwater (I just went out and checked).

 

[Jimrahbe]

T,

The number one reason that a spa will drain down to just below the spa jets, when the pump is off, is that the check valve (that is supposed to be in the Spa return line) is leaking...

When in the Pool mode, something has to make the spa spillover into the pool. It is usually one of two things..

1. There is a pipe on the pool return side that feeds water to the spa, when in the pool mode.
2. The Return valve, that sends water to either the Pool or the Spa is off-set so that it never fully shuts off the spa return line when in the pool mode.

If # 1, then the check valve must be in the pipe that sends water to the spa, when in the pool mode.
If # 2, then the check valve must be in the main Spa return line.

Tell us what cause your spa to spillover into the pool or show as several pics of your equipment pad.

Your problem has nothing to do with the suction side of your system..

Thanks,

Jim R.

 

[Tfastle]

The spa does not act as a water feature. While there is a "spillway" it's only for filling or topping off the spa. If I want to use it as a spill way it would basically just be having the spa in "fill' mode (both 3way valves fully open to the spa side). When the valves are in "pool mode" no water is actively directed to or from the spa - both the suction and return 3way valves are in the fully closed position with regard to the spa.

After the pump pushes the water through the filter and heater there is a check valve then the automatic chlorinator, then a 3way valve - one to the spa returns, one to the pool returns. There is no check valve on either. Pool water level is below all 3way vales. Spa level is about 15 or so inches above the 3way valves. After this discussion it appears to me that a check valve should be on the spa return lines and I will likely put one in.

But it's not clear to me why the problem couldn't be on the suction side? When the pump is off (a great deal of the time) and the valves are left in "pool mode" why couldn't water be seeping by the 3way valves at either or both valves - suction or return side? Neither has a check valve. It seems to me that what I thought was happening at the suction 3way may or may not be happening but it also may or may not be happening at the return 3way. It really seems to be the same situation on both sides - when the pump is off the elevated spa water is is pushing against the 3way valve and could be seeping by and back into the pool. Or am I missing something?

If were to add one of the check valves, or both, what type or brand might be best used for this purpose. As mentioned before, I am leaning towards the Jandy spring/flip style with a sight glass top.

Thanks for the input.

At the moment I can't get pictures of the plumbing as I am not there. Access for clear pictures is a little trick as well because of a structure and winterization.

 

[mknauss]

How is the water in the spa chlorinated and filtered daily if there is no exchange of water between the spa and pool?

 

[Jimrahbe]

T,

The idea that the spillover is there to act as a water feature is just not correct. The whole point of the spillover is to keep fresh and sanitized water in the spa. Most people don't drain and refill there spa before each use.

It could be that your set up is not what we are used to seeing.

In any case, I've provide my input, and you are free to use it or not.. It is your pool/spa and you can run it anyway you want.

No matter where you add your check valve, it should be a Jandy style, with a clear lid.

Thanks,

Jim R.

 

[Tfastle]

I understand that a common practice would be to have a portion of the water diverted to the spa and overflow into the pool to keep the water clean and sanitized (our last pool was like that). Because we have a cover on the pool and automation that's not realistic unless the cover is opened every time the pool is pump is activated. With regard to managing the spa water, I have the automation set up to run daily in spa mode for a while for filtration purposes. There is also a cover on the spa so the chems are pretty stable but also, after I do my pool chems, I put the system in "Service" mode and run on spa "fill" to cycle the water through the spa so it is filled with water from the balanced pool water. It's actually a pretty simple pool to manage, partially thanks to this site because of what I have learned here with regard to chems.

I do appreciate all of the input. I think I was on the right track but I certainly had not considered the return side as the culprit and it definitely could be. I plan to use an optical level to compare the water level in the spa (the low point where it doesn't seep down any further) with the suction 3way and the return 3way (the both are ar the high points of their respective loops yet different elevations). My guess is that the "seeped off drain level" will be the same as one or the other of those 3way valves. If it's the higher one (the suction) It seems that means that is where the problem is. If it's the lower, then it could be both of them or just the lower 3way (the return). From there I'll install the check valves as needed.

Not sure when I will do it but once I do I will reply back here with the results.

Again, thanks for the thoughts and information, it was very helpful.