Plumbing question - returns

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freerider_tx

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May 11, 2013
10
Austin, TX
Hi - I am under construction in DFW! :) It's a freeform gunite pool with spa, approximately 12,000 gal. I have a Jandy VSP (VS-FHP2.0) pump for the pool/spa, a separate pump for water features (sheer descent and 3 bubblers), and a booster pump for Polaris 280. The pool has 5 returns and 2 skimmers and the spa has 6 jets.

My question is on the returns to the pool. There is one 2" pipe from the pad that splits into 2 1.5" pipes after about 5'. One of the 1.5" lines feeds 3 returns and the other 1.5" line feeds the other 2 returns. Is this adequate?

Any feedback is appreciated!!
 
It depends on the layout of the plumbing and the length of each 1.5" pipe. Do you have a schematic that you can post?
 
photo_zpse39868e6.jpg


Ok - apologies for the quality of the drawing and it's clearly not to scale, but hopefully it provides the information you need. Thanks!
 
Loops don't help all that much were pipe length is long. They help more in spas where the loop around the spa is short. However, larger pipe certainly would help. I would go all 2" line and where it is TEED to the pool edge, then they can downsize to 1.5".
 
Ok thanks, I appreciate your response! That makes sense.

Would you say it is a problem the way it is done now, or just better to have the 2"? I'm not trying to question your advice, just trying to assess the magnitude of the issue.

Thanks again!
 
It is both an issue of energy efficiency and the smaller pipe can mean unequal flow rates to the returns. The larger the pipe, the less influence the pipe has on flow rates so if you up size the pipe, the flow rate to each return is more likely to be the more or less the same. It isn't a huge issue but I think you would be happier with the results with the larger pipe as it may help to prevent dead spots in the pool circulation. Plus pipe is cheap compared to the pool so up sizing shouldn't cost much.
 

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BTW, I noticed you have a spa. Unfortunately, there are a lot of pool builders that really don't know how to design a proper spa. So if your would post some more details about the spa, I can take a look at that as well.

Number of jets, type, nozzle size
Pipe size
Distance to the pad
Jet Pump Model

Here is a quick reference on spa design:

The first step in designing a spa is to settle on the number of jets, size of jet and how strong you would like the jet to feel. Once this is determined, the following table can be used to determine the proper pipe size and the resultant operating point for the pump.


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The following example will help the reader understand how to use the sizing table:

Jet Design: 6 x 3/8" Jets @ 15 GPM/Jet

Total Flow Rate = 90 GPM
Minimum Recommended Pipe Size = 2.5"
~ Head Loss = 55' (assumes 100' of pipe and typical fittings for a spa)
Desired Pump Operating Point = 90 GPM @ 55' of head

A few 1 HP full rated pumps and most 1.5 HP full rated pumps would work well for this setup.

Also, note that for designs requiring more jets than a pipe or pump can support, multiple plumbing loops with multiple pumps can be used to achieve the necessary flow rates.
Click to expand...
 
Thanks, I have 6 jets, I'm not sure what size, but probably 3/8" (will have to check). There is 2.5" pipe running to the spa loop, it's about 40', maybe 35', and the pump is the Jandy VSP (VS-FHP2.0). The PB said typically they do 5 jets, but with our setup 6 would be ok.

We have a blower and I was thinking of adding venturi valves (I think that's what they are called - the spin valves on top of the coping) so that I could run the spa at night without the blower - but I guess this is not commonly done.
 
How long and what size is the air pipe? If you up size the air pipe and make it straight, you shouldn't need a blower. Just make sure he puts in a Hartford loop near the spa to prevent the air pipe from filling up with water.
 
Not sure about some of the terminology. By 'air pipe' do you mean the loop in the spa? The spa perimeter is about 25' and the air line is 1.5" and the water line is 2". I googled 'Hartford loop' and, yes, there is one. We added the blower as a backup, PB agreed we probably don't need it. The air line from the blower to the spa air loop is 2".

So Venturi valves on coping are not needed?
 
The air line goes from the spa back to the equipment pad where the blower would be installed and I would up size that to 2.5" just to make sure.

But your forum name changed?
 
austin.sailor said:
So Venturi valves on coping are not needed?
Click to expand...
Sorry forgot this. These are nice to have but are not needed. Some people like the bubbles and others don't so this would give each their own control. The valves would replace the air line.
 

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