Blocked pipe

Caliguian

Member
Aug 21, 2021
10
Southern Utah
I have a 13,800 gallon inground fiberglass pool that has a blocked return line somewhere under the concrete, and I'm not sure what to do about It. I've pressurized the line with air to see if anything can get through at all, and it seems to get to about 45psi before the air manages to get through and the pressure releases, but then after it's been blown out with air still no water can get through when it's repressurized with the pool pump (it sits at 30psi doing nothing).

I've sent a camera through the piping, and there was no blockage as far as the camera could get (about 25 feet) before the pipe turned too sharply for the camera to get past. I then used a detector to locate where the camera was getting to, and it gets right up next to edge off the pool, on the opposite end from the jets (about 30 feet from the return jets) before it gets stopped and can't go any further due to the pipe angle. So, I know there isn't a clog of any type up to that point. I tried sending the camera down the jets themselves, but the jet piping isn't quite large enough for the camera to get through there. What I'm left with is a blockage somewhere in the piping along the thirty foot edge of the pool, under the concrete, and I can't seem to pin it down any further than this.

Any advice? I'd hate to try to cut the edging of the pool off in order to get to the piping to find the blocked area, so I'm thinking I may try to cut the cement parallel to the edge, about a foot or two away from the edge, all thirty feet down the side of the pool, and re-lay new piping instead. That's a pricey (and labor intense) job to do though, so I'm hoping that someone here might have a better solution.

Thanks!
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
14,031
Houston, Texas
Hi, welcome to TFP! Have you traced the pipe back to the equipment pad? Are there any valves on that pipe, or does it connect to a manifold of pipes? Is this return placed at the same level as other returns or does it appear to be deeper or shallower in the water? How long do you think the line has been blocked? Any photos you can post may be helpful.
 

Texas Splash

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Jun 22, 2014
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You mentioned air. Have you tried a pressure bladder? Something like a Drain King or the one below?

full
 

Caliguian

Member
Aug 21, 2021
10
Southern Utah
Hi, welcome to TFP! Have you traced the pipe back to the equipment pad? Are there any valves on that pipe, or does it connect to a manifold of pipes? Is this return placed at the same level as other returns or does it appear to be deeper or shallower in the water? How long do you think the line has been blocked? Any photos you can post may be helpful.
The line has only been blocked for a couple of weeks so far.

Our setup is pretty simple; there is just one pipe coming out of the ground (drain and skimmer meet somewhere underground) that goes into the pump, and then one return pipe that heads back underground after running through the filter and chlorinator. The return pipe runs to the two return jets using a single pipe that just has a T at the first jet and ends at the second jet. I'll attach some pictures.

I tried pressuring the system from the return jets today (using an air compressor) to see if it might loosen things up by pushing it from the opposite direction, but unfortunately aside from letting air through at about 20psi it didn't do much to loosen up whatever's clogging or kinking it up.pool_blockage_diagram.jpgpool_side_x_03.jpg

(It doesn't look like I have an image of the return going underground, but it's just out of the frame... It's just a pipe going down.)
 

Caliguian

Member
Aug 21, 2021
10
Southern Utah
You mentioned air. Have you tried a pressure bladder? Something like a Drain King or the one below?

full
I haven't tried an air bladder yet, but I'm not sure how well it would work since so far I haven't actually found where the clog or kink is. Does something like this fit through 90 degree corners without getting stuck? I also saw something similar on Amazon that looks a little smaller, and I was considering trying that as well. Amazon.com: Sewer Jetter - 50 FT JetSnake Drain Cleaner for Your Gas Pressure Washer : Patio, Lawn & Garden
 

reggiehammond

Gold Supporter
Oct 4, 2020
360
Fort Worth, Texas
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This may be a stupid idea; but you’ve ensured your filter is not plugged? What happens if you disconnect the union to filter and run pump. Good flow?

I’ve unclogged a pipe with a water hose; but you may not have the clearance to get it down in there from the 90 underground…
 

Caliguian

Member
Aug 21, 2021
10
Southern Utah
This may be a stupid idea; but you’ve ensured your filter is not plugged? What happens if you disconnect the union to filter and run pump. Good flow?
Yeah, it's a good idea, but I've checked the filter and all is well there. When I disconnect the return line just before it heads underground and then test run the pump, all works normally and TONS of water comes through from the filter.
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
14,031
Houston, Texas
Yeah, it's a good idea, but I've checked the filter and all is well there. When I disconnect the return line just before it heads underground and then test run the pump, all works normally and TONS of water comes through from the filter.
Just to make sure I have this straight, you have run a camera from where the return line leaves the filter and it stops where the pvc changes from the rigid pvc at the pad to flex pvc leading to the returns. If this is correct then I'm thinking you may have a collapsed flex line shortly after the plumbing joint with the rigid pvc. It would be pretty hard for something large enough or volumenous enough to get sucked into the skimmer, past the skimmer basket, past the pump strainer basket, through the filter and get stuck in the return line and block off return flow. A collapsed flex pipe could be pinched off enough to only allow a trickle of water through and temporarily hold air pressure until it opens the pipe enough to release the pressure.
 
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Caliguian

Member
Aug 21, 2021
10
Southern Utah
Just to make sure I have this straight, you have run a camera from where the return line leaves the filter and it stops where the pvc changes from the rigid pvc at the pad to flex pvc leading to the returns. If this is correct then I'm thinking you may have a collapsed flex line shortly after the plumbing joint with the rigid pvc. It would be pretty hard for something large enough or volumenous enough to get sucked into the skimmer, past the skimmer basket, past the pump strainer basket, through the filter and get stuck in the return line and block off return flow. A collapsed flex pipe could be pinched off enough to only allow a trickle of water through and temporarily hold air pressure until it opens the pipe enough to release the pressure.
Yeah, that's what I'm afraid has happened as well. If I had a way of knowing where specifically the pipe had pinched along that edge I wouldn't need to cut out 30 feet of concrete (to put in a replacement pipe) but unfortunately I guess that's the next step. I appreciate your comments and input.
 

Caliguian

Member
Aug 21, 2021
10
Southern Utah
Yeah, that's what I'm afraid has happened as well. If I had a way of knowing where specifically the pipe had pinched along that edge I wouldn't need to cut out 30 feet of concrete (to put in a replacement pipe) but unfortunately I guess that's the next step. I appreciate your comments and input.
I was able to narrow things down to a 4 foot section instead of a 30 foot section. The return jets were too small for a camera or a hose to fit through, but I found some 1/4" irrigation tubing that I was able to snake through the plumbing going backwards from the jets. Based on how far I was able to get the 1/4" tubing to go through before hitting a dead end, I believe I know (roughly) where the collapsed pipe is. I have a concrete cutting company coming out next Tuesday to pull out the concrete from the area that I believe the problem is, and I'll update this thread with the results of that. Wish me luck!
 

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phonedave

Well-known member
May 30, 2012
975
Montville NJ
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Got it! I cut the cement where the suspected blockage was, and then I dug it out and found this...

Not sure how it happened, but at least it doesn't look like a difficult fix at this point (besides pouring the new concrete).

Not sure how that would happen either. Good job locating and exposing the problem.
 

Texas Splash

Mod Squad
TFP Expert
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Jun 22, 2014
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Wow. That hose sure traveled. Great catch! :wave: To some degree you must be relieved. Now a straight-forward repair, some cosmetic work above, and you're back in business.
 

Caliguian

Member
Aug 21, 2021
10
Southern Utah
Here's a related question: now that I've dug the pipes up, should I replace the flex pipe altogether with rigid pvc? I dug out enough of the dirt to find both ends of the flex pipe, and I'm wondering if I should just replace the whole section with standard pvc. Or is flex pipe better for the corners in pool returns?
 

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ferretbone

In The Industry
May 24, 2016
143
tx
No hard plumb that back. I wish I could have caught this thread sooner. This was a fun read tonight, don't get me wrong it did S for you I'm awhere. I was thinking a busted leaking pipe but whatever. Hard plumb it back man. You have all the room you need.

Cut that coupling off, put a sweep on bothe sides facing up. and plug your horse shoe into the two 90 sweeps. done.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
28,525
Northern NJ
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Get rid of all the flex PVC you can. As you see it only causes problems.
 

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