Question re: pool return lines.


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Old 04-19-21, 12:21 PM
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Question re: pool return lines.

I need to replace one of my pool return lines as it has developed a leak somewhere under the concrete pad that surrounds the pool.
All existing lines are 1 1/2" 100 PSI poly pipe (blue stripe). This is no longer available in my area and would cost $300+ to special order a 100'roll.
Can I use 1 1/2" 75 PSI without any problems for this one return line?
Pool is 24 x 32'. This return is for the shallow end and the pipe run will be approx. 70' overall.
 
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Old 04-19-21, 02:05 PM
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75 psi pipe is more than enough for that application. The return line is negative pressure so no problem regarding burst strength.
 
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Old 04-19-21, 02:47 PM
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THANKS! I appreciate your reply. Tom.
 
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Old 04-19-21, 03:28 PM
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By return you are referring to a suction line ?

I usually call the lines from the filter TO the pool returns.
A return would have no more than 30-40psi on it and that would be high.
Since the return is open ended..... pressure doesn't build.

Pool plumbing in general is low pressure.
A suction line would have a vacuum on it.

Standard 1-1/2" black poly is fine for the job.

If you have a leak in the return line..... you'd get water coming out of the ground.
A leak in a suction line usually pulls in air and is noticed at the pump.
 
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Old 04-29-21, 08:24 AM
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Thanks!

Thanks for the info. Much appreciated.
I have run the new line and everything tests out OK.
I had to tunnel under the concrete pool deck to install it.
The concrete is reinforced and approx. 3 1/2" thick on average. The slab is 44" from the front to the pool edge
It extends approx. 18" on both sides of the tunnel (left and right in the photo). Clear as mud?
My concern is that this section of the decking is already 1/2" lower on the near side (in the photo) than on the pool wall side. It has sunk slightly over the past 38 years, I guess.
Do I need to put a support under the slab to help prevent further shifting caused by the tunneling? Or just pack the sandy soil back under it?
If it would benefit from a support - any recommendations?

 
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Old 04-29-21, 09:42 AM
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Yes, you need to do something to support the concrete. I would back fill the hole with a easily compacted material like sand or protect the piping and use a gravel like #75. Then use a structural foam to fill the remaining gap to support the concrete.
 
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Old 04-29-21, 10:01 AM
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My pool is a little older than yours (50+) but with the same deck problem.
It's almost impossible to do anything with the deck where it where it joins the pool coping.
 
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Old 05-03-21, 01:38 PM
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@Pilot Dane: Can you please explain about using structural foam? Do you mean using an expanding spray foam to fill the gap between the top of the sand and the bottom of the concrete? I presume I'd do this in stages as the hole is filled and tamped as high as can be done (looks like I can get it to within 2" of the bottom of the concrete). Otherwise the foam wouldn't be able to reach very far back into the gap.
Or did you mean using some type of foam board?
 
 

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