Owner Build - Plumbing Design Help

zarlar

Member
Feb 4, 2021
6
Las Vegas, NV
Hello,

My wife and I started an owner build for a 22'x40' rectangle pool including a 6'x9' raised spa and wet deck. My calculations have the pool and spa around 24,000 gallons and the plumbing run will be 80ft to the equipment pads. The pool has been excavated and we are trying to finalize the plumbing and equipment setup. Will you please help us with feedback/answers to the following questions? Thank you in advance!

We plan to run two 3hp variable speed pumps, two cartridge filters, and two skimmers because we want the pool to be extra clean and lower maintenance. We will also be installing two bubblers in the wet deck and hoping to run 8 spa jets. A plumber told us that he cannot find piping larger than 2.5".
  • Will a 3hp Pentair variable speed Spa pump be strong enough to run 8 spa jets with 2.5" plumbing and a spa cartridge filter at 80' distance?
  • Do we need additional spa returns in addition to the 8 planned spa jets? If so, how many?
  • How many drains do we need in the spa?
  • Will a 3hp Pentair variable speed Pool pump be strong enough to run 2 skimmers, 2 bubblers, pool main drain, and pool returns with 2.5" plumbing and a cartridge filter at 80' distance?
  • How many pool returns should we have?
  • In this Jandy two filter diagram could we run the heater for both pumps simultaneously?
1632283925355.png
Thank you for your patience and expertise! :)
 

cowboycasey

Gold Supporter
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Jul 3, 2013
8,648
Southern OK
Pool Size
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Surface
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Chlorine
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SWG Type
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You are close..

1. only 1 filter is needed.. with automation you will have a heater and filter on the pool and spa pump and be able to change between where the water goes when needed..

2. the spa pump will have no filter to supply more GPM to other ports needed.. The Spa pump will have dedicated returns back to the spa..
 

JamesW

TFP Expert
Mar 2, 2011
28,264
For suction, you want to keep the water velocity below 6 ft/sec.

For returns, you want to keep the water velocity below 8 ft/sec.

Size.......6 ft/sec......8 ft/sec.

1.5"...........38...............51 gpm

2"..............63...............84 gpm

2.5............90.............119 gpm

3.0".........138.............184 gpm

4”...........234.............313 gpm

For 8 jets at 20 gpm per jet, you need 160 gpm total flow.

That would require a 4" suction and a 3" return.

A 3" suction will allow up to 138 gpm, which is 17.25 gpm per jet (3" return).

A 2.5" suction will allow up to 90 gpm or 11.25 gpm per jet (2.5" return).
 
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zarlar

Member
Feb 4, 2021
6
Las Vegas, NV
You are close..

1. only 1 filter is needed.. with automation you will have a heater and filter on the pool and spa pump and be able to change between where the water goes when needed..

2. the spa pump will have no filter to supply more GPM to other ports needed.. The Spa pump will have dedicated returns back to the spa..
Hi cowboycasey, thank you for your reply.

What would this setup look like? Would it be same as above minus the spa filter? Please provide a drawing or diagram if possible.

How many spa returns do you recommend?
 

zarlar

Member
Feb 4, 2021
6
Las Vegas, NV
For suction, you want to keep the water velocity below 6 ft/sec.

For returns, you want to keep the water velocity below 8 ft/sec.

Size.......6 ft/sec......8 ft/sec.

1.5"...........38...............51 gpm

2"..............63...............84 gpm

2.5............90.............119 gpm

3.0".........138.............184 gpm

4”...........234.............313 gpm

For 8 jets at 20 gpm per jet, you need 160 gpm total flow.

That would require a 4" suction and a 3" return.

A 3" suction will allow up to 138 gpm, which is 17.25 gpm per jet (3" return).

A 2.5" suction will allow up to 90 gpm or 11.25 gpm per jet (2.5" return).
I think I found some 3" piping in stock locally (not sure why the plumber said he could not find it in the past).

Would we need 3" piping only for only the suction lines or also for the return lines?

Do you agree that the spa pump should not have a separate filter?
 

JamesW

TFP Expert
Mar 2, 2011
28,264
Would we need 3" piping only for only the suction lines or also for the return lines?
How much flow per jet do you want to have?

For 8 jets at 20 gpm per jet, you need 160 gpm total flow.

That would require a 4" suction and a 3" return.

A 3" suction will allow up to 138 gpm, which is 17.25 gpm per jet (3" return).

A 2.5" suction will allow up to 90 gpm or 11.25 gpm per jet (2.5" return).

Do you agree that the spa pump should not have a separate filter?
You can do a separate pump and filter if you want both to run at the same time.
 

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zarlar

Member
Feb 4, 2021
6
Las Vegas, NV
How much flow per jet do you want to have?

For 8 jets at 20 gpm per jet, you need 160 gpm total flow.

That would require a 4" suction and a 3" return.

A 3" suction will allow up to 138 gpm, which is 17.25 gpm per jet (3" return).

A 2.5" suction will allow up to 90 gpm or 11.25 gpm per jet (2.5" return).


You can do a separate pump and filter if you want both to run at the same time.
I would be happy with the 17.25 gpm per spa jet. Now that I reread your reply I see that it says 3" returns :). So I will plan for 3" suction and return lines.

Yes I would like to run both at the same time, but would a filter on the spa pump reduce the flow too much?
 

JamesW

TFP Expert
Mar 2, 2011
28,264
Yes I would like to run both at the same time, but would a filter on the spa pump reduce the flow too much?
I would use a CCP520 cartridge filter.

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9.5 psi is about 22 feet of head.

1632325374418.png
The heater should have a check valve bypass.

You can do a 2 lb or 3.5 lb spring check valve.

A 2 psi check valve should remain closed until the flow rate hits 60 gpm, which is more than enough for any heater.

At 60 gpm, the check valve should open and begin bypassing some water around the heater.

If you have a regular Jandy check valve at the heater outlet as part of a manual bypass, I would put the spring check valve bypass on the inside of the check valve.

So, you would have the heater, spring check valve bypass and the manual bypass all in parallel.

Y is a three way valve.
X is a spring check valve bypass.
Z is a flow switch.
O is a regular Jandy check valve.


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1632326005789.png

I would estimate the head loss from the plumbing at about 12 feet.
From the heater at about 14 feet.
Plumbing + Filter + Heater = 48 feet at 138 gpm.

The Intelliflo can do 140 gpm at 55 feet of head, so that should work.

1632326609268.png
 
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