A mystery loop in my pool plumbing

[miamicuse]

When I purchased the property a few years ago, I had planned on redoing the existing plumbing. However, there is a mystery loop in my pool return line that I could not figure out why it was there. Later on a fitting on that loop started leaking, and in an attempt to fix that leaking fitting, I cut that loop off without knowing why that loop was there in the first place.

This loop is on the return line, it enters a 3 way valve - one end goes to the pool, the other end goes to the spa. So the two return lines run back below grade to the pool and spa, but there are two tees on each of the return line, connected to each other on a U shaped loop, with a shut off valve and a check valve. Here is a picture of the top view.

Here is a picture of this loop from the side.

Here is a schematic of my overall pool plumbing around the pump.

The portion on the mystery loop enlarged.

At the time due to the fitting leak, I couldn't figure out the purpose of this loop, or if there is a purpose...so I cut the loop out and capped both ends like this. It stopped the leak and the removal of this loop didn't seem to make any noticeable difference.

but I keep thinking this must have been done for a reason just that I don't know enough to realize what it's for. Does anyone know what purpose this loop was designed for? I am considering redoing some pool plumbing and am wondering if I redo it whether I should consider reconnecting it back.

 

[1poolman1]

When I purchased the property a few years ago, I had planned on redoing the existing plumbing. However, there is a mystery loop in my pool return line that I could not figure out why it was there. Later on a fitting on that loop started leaking, and in an attempt to fix that leaking fitting, I cut that loop off without knowing why that loop was there in the first place.

This loop is on the return line, it enters a 3 way valve - one end goes to the pool, the other end goes to the spa. So the two return lines run back below grade to the pool and spa, but there are two tees on each of the return line, connected to each other on a U shaped loop, with a shut off valve and a check valve. Here is a picture of the top view.

Here is a picture of this loop from the side.

Here is a schematic of my overall pool plumbing around the pump.

The portion on the mystery loop enlarged.

At the time due to the fitting leak, I couldn't figure out the purpose of this loop, or if there is a purpose...so I cut the loop out and capped both ends like this. It stopped the leak and the removal of this loop didn't seem to make any noticeable difference.

but I keep thinking this must have been done for a reason just that I don't know enough to realize what it's for. Does anyone know what purpose this loop was designed for? I am considering redoing some pool plumbing and am wondering if I redo it whether I should consider reconnecting it back.

That is your spa overflow. It was put there to allow some filtered water to enter and overflow the spa to keep chemicals in the spa and the water relatively fresh. If the spa is the same level as the pool it only takes opening the spa-return valve a bit to do the same thing. If you have a dedicated spa line that is open during normal pool filtration it isn't needed.

 

[miamicuse]

so it's purpose is to basically send water to the spa from the pool. The white ball valve with the black handle is to open for this to happen?

So the higher 3 way valve is set to return to the pool, but the lower loop's ball valve will open to allow water to also go to the spa at the same time, but wouldn't the spa overflow with extra water since the suction side from the spa is closed off?

Why is there a check valve on this loop to prevent water from backing into the pool from the spa?

If the idea is to divert some water to the spa, wouldn't you just turn the 3 way valve at an angle to allow water to go to both?

 

[Jimrahbe]

M,

It is called a "Make-up Line". Its sole purpose is to force your spa to spillover into the pool when you are in the Pool mode.

Without that line, no fresh water would ever go to the spa and the spa would turn green.

Is your spa built so that it overflows into the pool?

Show us a couple of pics of your Spa.

Thanks,

Jim R.

 

[miamicuse]

M,

It is called a "Make-up Line". Its sole purpose is to force your spa to spillover into the pool when you are in the Pool mode.

Without that line, no fresh water would ever go to the spa and the spa would turn green.

Is your spa built so that it overflows into the pool?

Show us a couple of pics of your Spa.

Thanks,

Jim R.

No, the spa is completely separated from the pool.

Here is a picture showing the spa and part of the pool. Ignore the water spilling into the pool I took the picture trying to figure out how to regrade the deck to have better drainage during king tides and non stop raining when we have a hurricane.



The pool plumbing is original from 1992 so is the spa and pool. I reviewed the pool plans and permits and it's been this way for 30 years. So someone plumbed this for an overflowing attached spa?

 

[Jimrahbe]

M,

Something is wrong. When the spa does not overflow into the pool, it should have its own equipment.

Think about it for a minute... If you did not use the spa for a few weeks, how would the spa water stay fresh and chlorinated. It would just become a stagnant pond.

Not all spas are raised, but they can still "spillover" in the pool. That said, it appears that your spa has decking in between the pool and the spa. Is that true?

If so then your spa should have a pipe that connects spa water the the pool water.. Instead of a "spill-over" it is more of a "under-under".

Does your spa have a mystery pipe of some kind? Does it have its own skimmer??

Do you have any pics when the spa is empty or at least at normal water level.

Thanks,

Jim R.

 

[miamicuse]

M,

Something is wrong. When the spa does not overflow into the pool, it should have its own equipment.

Think about it for a minute... If you did not use the spa for a few weeks, how would the spa water stay fresh and chlorinated. It would just become a stagnant pond.

Not all spas are raised, but they can still "spillover" in the pool. That said, it appears that your spa has decking in between the pool and the spa. Is that true?

If so then your spa should have a pipe that connects spa water the the pool water.. Instead of a "spill-over" it is more of a "under-under".

Does your spa have a mystery pipe of some kind? Does it have its own skimmer??

Do you have any pics when the spa is empty or at least at normal water level.

Thanks,

Jim R.

Hmmm...I don't think there is a connection between the spa and the pool. I will double check.

I have not owned a pool/spa before I bought this place a few years ago and I have been learning along the way.

There is a pool service that comes every week to clean and chlorinate, and they put chemicals in both the spa and pool, I have been meaning to do that all myself as they do not seem to really do much when they are here.

Occasionally, I will change the suction side valve to pull the spa dry and return the water to the pool, after that I change the suction side back to the pool, and the return side valve to the spa to refill the spa with water from the pool. This is how I manually change out all the water in the spa a few times a month. I just assumed that's how it has to be done. In fact I was in the middle of doing that, set return side to pool, set suction side to spa, and while it was emptying the spa I answered a phone call and forgot about it altogether, then 6 hours later I remember and the pump was running dry for hours (which resulted in air leak that have me spinning my wheels...)

Now, if there is indeed a pipe between the spa and pool, when I pulled all water from the spa, the pool water should back into the spa right? I do not think I have ever seen that.

 

[1poolman1]

Hmmm...I don't think there is a connection between the spa and the pool. I will double check.

I have not owned a pool/spa before I bought this place a few years ago and I have been learning along the way.

There is a pool service that comes every week to clean and chlorinate, and they put chemicals in both the spa and pool, I have been meaning to do that all myself as they do not seem to really do much when they are here.

Occasionally, I will change the suction side valve to pull the spa dry and return the water to the pool, after that I change the suction side back to the pool, and the return side valve to the spa to refill the spa with water from the pool. This is how I manually change out all the water in the spa a few times a month. I just assumed that's how it has to be done. In fact I was in the middle of doing that, set return side to pool, set suction side to spa, and while it was emptying the spa I answered a phone call and forgot about it altogether, then 6 hours later I remember and the pump was running dry for hours (which resulted in air leak that have me spinning my wheels...)

Now, if there is indeed a pipe between the spa and pool, when I pulled all water from the spa, the pool water should back into the spa right? I do not think I have ever seen that.

Is there a skimmer in the spa? Many times it acts as the overflow to the pool, not active as a skimmer. Most spas pull water from the main drain(s) and not the top of the body of water.

 

[proavia]

I have a friend with a pool/spa combo and both are at the same level. There is what amounts to an equalizer line/pipe between the pool and spa. When the pool pump is running, there is return water running to the spa - and then into the pool via this pipe. This allows chlorinated pool water to also flow into the spa, helping to keep the spa water chlorinated.

 

[mknauss]

There is what amounts to an equalizer line/pipe between the pool and spa.

How is that blocked when the spa is used as a spa?

 

[1poolman1]

How is that blocked when the spa is used as a spa?

Most commonly - tennis ball.

 

[Jimrahbe]

Marty,

I was under the impression that when the spa used a pipe for the "spillover" the opening was above the spa level, just like a traditional spillover is above the normal spa level..

Thanks,

Jim R.

 

[1poolman1]

Marty,

I was under the impression that when the spa used a pipe for the "spillover" the opening was above the spa level, just like a traditional spillover is above the normal spa level..

Thanks,

Jim R.

For years, at least in my area, many pool builders would build the dam wall the same height as the rest of the deck and put a piece of 2" pipe in the wall between the pool and spa about 18" below water level so the spa would not overflow out but would equalize with the pool. Some would provide a plug of some sort for that pipe when the spa was in use, but I only ever saw a tennis ball unless someone got a test plug. Problem was that you either had to get into a cold spa to plug it before use or wait a long time for the spa to heat, because the pool and spa water would co-mingle, then get in and plug it. Then, you had to remember to remove the plug or lose a bunch of water the next day.
I would sometimes extend that pipe out and, using a 90, put a vertical pipe in just above the water level that meant you didn't have to plug the pipe, but they intruded into the spa. Had a friend that used to saw-cut a notch in the top of the wall, tile it, fill that pipe with plaster and made a proper "overflow." Either way, customers were happy to be able to use their spa whenever they wanted without getting into cold water first.

 

[proavia]

How is that blocked when the spa is used as a spa?

I think he uses a racket ball. A tennis ball (as @1poolman1 suggested) would work too.

 

[miamicuse]

Is there a skimmer in the spa? Many times it acts as the overflow to the pool, not active as a skimmer. Most spas pull water from the main drain(s) and not the top of the body of water.

No skimmer for the spa, only skimmer for the pool.

I don't think there is return water from the pool to the spa, in the past when I want to change out all the water in the spa from the pool, I change the suction valve to spa and return to pool, when the spa is all drained, I reverse the valve direction to have suction from the pool and return to the spa.

If I do have another pipe that connects the pool to the spa, then when the spa is fully drained, I should have water coming back to the spa from the pool just from the unequal elevations of the two water bodies right?

Or may be, the other connection between the spa and pool IS the U shaped loop along the return line that I removed?

 

[Jimrahbe]

Or may be, the other connection between the spa and pool IS the U shaped loop along the return line that I removed?

M,

Got any pics of that one???

Jim R.

 

[miamicuse]

M,

Got any pics of that one???

Jim R.

Yes that's the "loop" that had me scratching my head and started this very thread, the loop that I eliminated because I had a leak on it, but I thought may be it did serve a purpose that I don't understand. So pics are in post #1. Now I my understanding is that loop is a make up line to divert some water from pool to spa, but only for a spa that spills over to a pool and not like mine when the pool and spa are separate. So now I don't know whether the original pool builder made a mistake to install this loop or it actually do something else.