Pool & Spa plumbing - Creating a virtual spillover

[cpotter638]

Have 16k gallon pool with automatic cover as well as an 800 gallon elevated spa. Because of the automatic pool cover, both the pool and spa have separate sand filters and variable speed pumps. As such, I have 2 separate chemistries to maintain.

I also just installed a heat pump for the pool. Our spa has a gas heater which is currently broke. I'm guessing it will not be worth the money to fix.

I'm interested in finding a way to combine both the pool and spa circulations with one pump and one filter. The spa as a main drain, but no skimmer.

Goals:
1) Combine pool and spa circulation with one sand filter and one pump.
2) When wanted, be able to heat only the pool with the heat pump.
3) When wanted, be able to heat only the spa with the heat pump.

Is the above possible? I'm thinking the biggest hurdle will be creating a "virtual spillover" for the spa to maintain correct water level in both the pool and spa. However, I have no experience and can find very little info on this topic.

Any help would be greatly appreciated. Thanks in advance. Chad

 

[Jimrahbe]

638,

I can't see how this can work unless you have an actual spillover.. It would not have to actually "spill" but water would have to flow between the spa and the pool..

Are things located in such a way that you can add plumbing between the pool and the spa??

Thanks,

Jim R.

 

[cpotter638]

Jim R,

Pool and spa plumbing is centralized in a utility room off the garage. Would be no problem to add plumbing between them.

Basically, I want the ability to have the pump circulate 1) only pool water, 2) only spa water, or 3) combined pool and spa water depending on valve settings. How actually would I plumb this "virtual spillover"?

Thanks. Chad.

 

[ajw22]

Basically, I want the ability to have the pump circulate 1) only pool water, 2) only spa water, or 3) combined pool and spa water depending on valve settings. How actually would I plumb this "virtual spillover"?

Chad, 1 & 2 are doable although I don't know if the ET would be able to handle the valves.

Combining the pool and spa water is the difficult one. The issue is balancing the inflow and outflow from the spa. Too much inflow with too little outflow and the spa will oveflow. Too little inflow and too much outflow and the spa will drain. A spillover does not have that issue because its outflow can vary and match the inflow of water. No easy way to have such a variable outflow from your "virtual spillover"

You can have valves move the pump/filter/heater from one body of water to the other. Neither needs to be filtered for a long period of time. So over a 24 hour day both bodies of water can take their turn being circulated and filtered. The issue is how you keep each body of water chlorinated. Can your SWG run on each body of water for enough time to generate the needed FC?

 

[cpotter638]

Combining the pool and spa water is the difficult one. The issue is balancing the inflow and outflow from the spa. Too much inflow with too little outflow and the spa will oveflow. Too little inflow and too much outflow and the spa will drain. A spillover does not have that issue because its outflow can vary and match the inflow of water. No easy way to have such a variable outflow from your "virtual spillover"

I considered tackling this project back in 2013. However, I was concerned that it was too much for me to handle. However, after installing the heat pump and now facing a broke gas heater, I want to attempt this project. In 2013, I posted about this and JasonLion replied:

"There are several ways to do this. The most obvious is to add a skimmer like drain to the spa at the right height. Unfortunately that is never an easy or pretty retrofit. The alternative is to create the same thing virtually somewhere else. The simplest way to do that is to tee off of your spa drain pipe (headed towards the pump), then a check valve so water only runs away from the spa in this new pipe, then run it vertically up to the height of the spa water, put on a T fitting with two vertical and one horizontal opening with the bottom of the horizontal opening right at the ideal spa water height. The horizontal opening then gets plumbed back to the pool (somehow). The vertical opening is left open to the air (to prevent syphoning), though it is best to put on a 180 bend so it points back down towards the ground. "

I considered PM'ing JasonLion as I have a couple of questions; however, I don't think he is as active on the forum currently. Has anyone installed a virtual spillover in this manner? I want to make sure something like this will work before I upend our pool plumbing.

You can have valves move the pump/filter/heater from one body of water to the other. Neither needs to be filtered for a long period of time. So over a 24 hour day both bodies of water can take their turn being circulated and filtered. The issue is how you keep each body of water chlorinated. Can your SWG run on each body of water for enough time to generate the needed FC?

This is an option; however, I would prefer to only have to deal with balancing one set of chemistries.

 

[cpotter638]

638,

I can't see how this can work unless you have an actual spillover.. It would not have to actually "spill" but water would have to flow between the spa and the pool..

Are things located in such a way that you can add plumbing between the pool and the spa??

Thanks,

Jim R.

Jim,

How would you plumb this being that I can connect the pool and spa plumbing? In a manner similar to what JasonLion suggested?

Thanks for the help. Chad

 

[Jimrahbe]

Chad,

Jason is a pretty smart guy, but at first glance I can't understand exactly how it will work.. I'm sure it is just me...

Let me take another look and see if I can understand Jason's theory of operation..

I'll get back with you later today as I have an appointment in a few minutes.

Jim R.

 

[Jimrahbe]

Chad,

Ok, I now understand what Jason was doing. The basic idea will work fine... IF you have a way to get water from the equipment house back to the pool without using a pressure or suction line. Do you have any lines that currently run from the pool to the equipment pad that are no longer used.. An old vacuum line maybe?

Here is a crude diagram...






Basically, you will need to plumb your system something like the above diagram.

When in the Pool mode, the water is sucked from your pool through the Intake valve and into the pump. It is them pushed through your filter and heater and then the Return valve sends the water back to the Pool.

When in the Spa mode, the water is sucked from your Spa through the Intake valve and into the pump. It is them pushed through your filter and heater and then the Return valve sends the water back to the Spa.

In the Spillover mode, the water is sucked from your pool through the Intake valve and into the pump. It is them pushed through your filter and heater and then the Return valve sends the water back to the Spa. Normally this would cause the Spa to spillover into the pool.. In your case, because of Jason's added pipes, the water will going down into the spa drain and then through a check valve and up to the same height as the max water level in the spa. It will then "spillover" inside the equipment room.

The key is how to get the water back into the pool.???? I am not sure what Jason had in mind?? If you had an old vacuum line you could use it or ?? Whatever it is, has to use gravity or a sump pump like mechanism. It can't be pool pump as water will not always be there.

Is this what you had in mind???

Jim R.

 

[cpotter638]

Jim,

First of all - I can't thank you enough for your time, explanation, and expertise. Thank you very much!

This IS what I had in mind.

I have an engineering degree; however, I have not had engineering job experience. As such, I like to understand how things work before I implement them. Still trying to wrap my head around some of the concepts in "spillover mode". I have several questions.

First and foremost - pool to spa connection:

1. Our pool has a tanning ledge. When pool was built, we put a water feature in the tanning ledge. Basically, we had 4 "fountains" installed in the tanning ledge that shoot vertically. This is operated with a separate cheap Pentair pump. Pump inlet / suction from deep end of pool and outlets into fountains. Pool builder had never done this before. They don't work like we anticipated. Tanning ledge is a little too deep and fountain flow is dampened quite a bit as it has to traverse the water volume in the ledge. As such, we occasionally use this feature, but not often.
2. I'm guessing our best option would be to have the "virtual spillover" outlet empty into the pump outlet of this water feature. Will this work???
3. Will we be able to use this water feature with this new setup? As you've drawn, I'm assuming answer would be no (pressure of water feature pump would shoot water out of open PVC.) But if check valve was either moved or added to piping between pool and open pipe, water feature would still work??? Would it work in both pool and "spillover" mode? Or just pool mode?
4. We have no abandoned vacuum line.
5. Our pool deck is made of Belgard pavers. We had a PVC run from equipment room to a location adjacent to pool in the event that we wanted to add a water slide in the future. This is obviously not ideal as we'd have to remove pavers, find the line, and somehow connect to pool. This would certainly be beyond my level of expertise (but could be done by a pool professional).

Again, thanks for all the help!
Chad

 

[Jimrahbe]

Chad,

Seems like you bubbler idea would work just fine... Something like this..




The overflow water from the spa would fall into a tank which is connected to your bubbler pump's pressure side. When the bubbler pump is off, any water above the pool level would drain back into the pool through the bubblers.. When the bubbler pump was running the bubblers would still work and the check valve would keep water from going into the tank. Obviously, you could not run the spillover at the same time as the bubblers.

Another key would be the volume of the spillover.. It would have to be low enough so that the tank never overflowed.. Pretty easy to do with a VS pump.

Thanks,

Jim R.

 

[cpotter638]

The overflow water from the spa would fall into a tank which is connected to your bubbler pump's pressure side. When the bubbler pump is off, any water above the pool level would drain back into the pool through the bubblers.. When the bubbler pump was running the bubblers would still work and the check valve would keep water from going into the tank. Obviously, you could not run the spillover at the same time as the bubblers.

Another key would be the volume of the spillover.. It would have to be low enough so that the tank never overflowed.. Pretty easy to do with a VS pump.

JasonLion mentioned 2 similar approaches to the "virtual spillover":

"It is possible to replumb things so that the two share water, but it is a fairly major job. The main trick is to create a virtual spillover, basically a small tank that is connected to the spa return and has a drain pipe going back to the pool. It will also need a check valve, so the spa pump can't draw air from the spillover tank."

Then a later post:

"You want to emulate a spill over, that means something that drains water when the water gets higher than standard spa height and sends the drained water to the pool. It is also important that this connection not create a syphon (so it won't continue draining).

There are several ways to do this. The most obvious is to add a skimmer like drain to the spa at the right height. Unfortunately that is never an easy or pretty retrofit. The alternative is to create the same thing virtually somewhere else. The simplest way to do that is to tee off of your spa drain pipe (headed towards the pump), then a check valve so water only runs away from the spa in this new pipe, then run it vertically up to the height of the spa water, put on a T fitting with two vertical and one horizontal opening with the bottom of the horizontal opening right at the ideal spa water height. The horizontal opening then gets plumbed back to the pool (somehow). The vertical opening is left open to the air (to prevent syphoning), though it is best to put on a 180 bend so it points back down towards the ground.

(This is simpler than the tank approach I mentioned before)."

Questions:

• Would I need a holding tank? Or will a more simple PVC conduit like Jason suggested in his second post suffice?
• If we need to have the tank, what approximate volume are we talking about?

Another key would be the volume of the spillover.. It would have to be low enough so that the tank never overflowed.. Pretty easy to do with a VS pump.

• Pump flow would have to be high enough to satisfy both our SWG and heat pump.

 

[Jimrahbe]

The only time you would need to worry about water coming into the tank would be when running the spillover.. Most of the time you would be either in the Pool mode or the Spa mode. I would only run the spillover a couple of times a day to keep the spa fresh and sanitized.

I think you would need a tank and it would have to be 30 to 50 gallons.. But to be honest, I'm just guessing.. It would have to be something you would need to experiment with and then decide. The key would be how fast does the water drain from the tank and back into the pool. It might be so fast that the tank would not need to be so big, but it has to be big enough to hold the water that came in faster than it could drain.

If this were my pool, I might try a 6" DWV pipe about 6 foot long and see if that would work.. The key, of course, is that it has to fit in your pump room and the top and bottom of the tank or pipe has to be determined by the level of the water in the pool and the water in the spa.

Thanks,

Jim R.

 

[cpotter638]

Jim,

This is finally making sense to me. Have you seen / installed such an arrangement? I'm surprised this is not more commonplace. For those that have an automatic cover and both pool and spa, this plumbing scenario makes much more sense to me than our current setup with duplicate circulations.

 

[mas985]

One thing to be aware of is that the flow rate from the overflow would need to match that of the flow rate from the pool into the spa while in spillover mode. This means that the overflow pipe would need to be very large to accommodate the higher flow rate with little head loss. Any additional head loss in the overflow pipe would result in an equivalent rise in the spa water level. Too much rise and the spa overflows.

 

[Jimrahbe]

Jim,

This is finally making sense to me. Have you seen / installed such an arrangement? I'm surprised this is not more commonplace. For those that have an automatic cover and both pool and spa, this plumbing scenario makes much more sense to me than our current setup with duplicate circulations.

I have not seen this before.. I just got intrigued with Jason's posts and thought it would be fun to try and understand how his idea would work..

I see it as a big project and with a lot of trial and error before it will work well.

One thing that I did not even look at is your automation. It sounds like your automation controls the two bodies of water separately. I am not sure it has the option to control them as a single body of water..

Thanks,

Jim R.

 

[cpotter638]

One thing to be aware of is that the flow rate from the overflow would need to match that of the flow rate from the pool into the spa while in spillover mode. This means that the overflow pipe would need to be very large to accommodate the higher flow rate with little head loss. Any additional head loss in the overflow pipe would result in an equivalent rise in the spa water level. Too much rise and the spa overflows.

Am I thinking about this correctly? In spillover mode:

• Q (pool->spa) = Pipe Area (pool->spa) * Velocity (pool->spa) = Q (overflow) = Pipe / Tank Area (overflow) * Velocity (overflow)
  • Need to decrease pump speed as much as possible
  • Need to increase Pipe / Tank Area (overflow) as much as possible

How large would overflow pipe diameter / tank area need to be? Piping from pool and spa to equipment room is 2".

 

[cpotter638]

One thing that I did not even look at is your automation. It sounds like your automation controls the two bodies of water separately. I am not sure it has the option to control them as a single body of water.

This was my next area of questioning. I'm certainly naive in regards to our pool automation. We have an Easy Touch (8) system. I have never fully understood the ideal pool / spa setup for the Easy Touch or whether the Easy Touch was truly designed to control BOTH the pool and spa. Our programming doesn't seem to be ideal for sure.

Our current Filter / AUX buttons control:

• F = Spa
• 1 = Pool
• 2 = Bubblers
• 3 = Lights
• 4 = Spa air blower
• 5 = Pool fountains
• 6 = Spa jets

We currently have 2 Jandy valve actuators (1 for spa and 1 for pool).

Spa has a chlorine feeder. Pool is chlorinated with an IC20. However, IC20 is tied to the spa. As such, pool cannot be chlorinated without spa pump on. This is certainly not energy efficient.

I have recently installed a Hayward heat pump (that is not currently controlled by the Easy Touch). We also have a now working Pentair gas heater for the spa (which is controlled by the Easy Touch).

My plan was to read the Easy Touch manual from front to back and get a better understanding on how it works. In my mind, with this new proposed setup, we are:

• Decreasing # of pumps from 3 to 2. Variable speed pump as wells as additional pump for bubblers.
• Increase # of modes from 2 to 3. Pool, spa, and spillover.
• Increasing number of valve actuators (not sure how many we need).

Is the EasyTouch 8 capable of this new proposed arrangement?

 

[Jimrahbe]

Chad,

I believe that the IntelliTouch has a model that controls the Pool and Spa as two separate bodies of water, but I do not believe that the ET 8 does. I'll check and get back with you..

The normal ET 8 would be perfect to control the pool and Spa as one body of water and has the ability to switch back and forth between the Pool mode and Spa mode, as well as run in the Spillover (Spillway) mode. Switching between the pool and spa is a built in function, so very easy to set up... the key is to have the Intake Valve and Return Valve set up as my crude drawings show..

Thanks,

Jim R.

 

[mas985]

Am I thinking about this correctly? In spillover mode:

• Q (pool->spa) = Pipe Area (pool->spa) * Velocity (pool->spa) = Q (overflow) = Pipe / Tank Area (overflow) * Velocity (overflow)
  • Need to decrease pump speed as much as possible
  • Need to increase Pipe / Tank Area (overflow) as much as possible

How large would overflow pipe diameter / tank area need to be? Piping from pool and spa to equipment room is 2".

You need to first design the layout so you know pipe lengths and fittings after which you can determine head loss for a given flow rate and then pipe size. Where you planning to tap into the spa suction line at the pad? If so, then that head loss will dictate how fast (RPM) you can run the pump. Slow enough and it won't matter much but you would need to do the calculations to make sure.

In fact, if you run slow enough, you should be able to tap into the spa suction line at the pad and re-inject to either the bubbler or MD lines at the pad if you are not going to use those. You shouldn't need the tank or additional pumps but the line will still need to be vented to break the siphon so the spa does not drain to pool level.

 

[cpotter638]

You need to first design the layout so you know pipe lengths and fittings after which you can determine head loss for a given flow rate and then pipe size. Where you planning to tap into the spa suction line at the pad? If so, then that head loss will dictate how fast (RPM) you can run the pump. Slow enough and it won't matter much but you would need to do the calculations to make sure.

In fact, if you run slow enough, you should be able to tap into the spa suction line at the pad and re-inject to either the bubbler or MD lines at the pad if you are not going to use those. You shouldn't need the tank or additional pumps but the line will still need to be vented to break the siphon so the spa does not drain to pool level.

I'm planning on tapping into the spa suction line / main drain at the pad and re-inject into the bubbler return line (also at the pad). Don't know pipe length or number / type of fittings yet. Want to first determine what automation can and can't handle.