90 elbow black abs: hair line crack

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  #1  
Old 06-08-19, 04:25 PM
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90 elbow black abs: hair line crack

So I am perplex. We discovered a water leak. Very long story I determined that the 90 elbow on the bottom of my stink pipe has a hair line crack. We have never had a water leak issue before, the affected wood has no side of long term wetness, etc. I proved it by getting up on the roof, and putting a garden hose in the stink pipe.

As luck would have it, the elbow is buried inside a bunch of other pipe work, and flooring joists, so its looking like a big job to get at it. Might have to remove a bunch of other pipe first.

But why would an elbow develop a hair line crack? It would never have frozen. And there is no water in there because its the stink pipe.
 
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Old 06-08-19, 05:08 PM
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Stink pipe=vent ? or do you mean the actual drain?

Crack could've been caused by a number of things. Defective to begin with, stress being applied by the way it's fitted to the other pipes, or maybe movement from the floor joist. Who Knows? Can you send a few pics so we can get a better view what your looking at?
 
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Old 06-08-19, 05:35 PM
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I'll try to get a picture but it won't reveal much. Yeah its the vent pipe, or vent stack pipe as some call it I think. It comes down from the roof, then there is a 90 elbow, and after just a few inches of pipe another 90 takes it down vertical again. Looks like a plumbers boo boo if you ask me; no clue why it would have not been a straight run. I'd tried to wiggle the pipe and its as tight as tight can be, no play in it.

Replacing it will be a big job, since it's 'boxed' in between a joist and other plumbing. As much as I am a fan of doing it right, I'm wondering about 'workarounds' like some sort of rubber hose clamp kit since its not a drain pipe. But since its an elbow I'm not sure.
 
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Old 06-15-19, 03:32 PM
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Hi,I had a similar problem about 30 years ago. ABS leaking at a joint (was in service about ten years) I cleaned the joint and put ABS solvent (glue) around joint, a couple of coats. It is still working. If that fails I would try epoxy, that stuff sometimes works miracles.
Good Luck Woodbutcher
 
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Old 06-15-19, 04:24 PM
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I would try what Woodbutcher suggest. It's not under any pressure to speak of and with enough glue and or J-B Weld Epoxy I think you'll OK.
 
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Old 06-22-19, 04:28 PM
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Norm201 I am pretty sure it was under pressure. The section of pipe had to 90 elbows (to go from vertical, horizontal and then back to vertical) and also two 22.5 elbows rotated 180 to create some vertical off-set. This 'configuration' was wedge between a flooring joist, the main sewer tee, and a non-load-bearing partition (wall). I think with some house settlement (over the course of 20+ years) plus a bit more loading on the floor above (I put down cement board, ceramic tile, and a new 300lbs vanity thanks to stone top) I think caused the hairline crack in the elbow. Although it took me quite a few hours I was able to replace the whole section and now there is a little 'give' in the pipe. I'll do a leak test tomorrow, and a little bit of strapping to provide some strain relief so I should be go for as long as I am in this house.

But I did want to ask another question. To keep rain water out of my vent stack until I got the repair done I put two 90 elbows (to make a 180 'goose neck) on my vent stack. I have no reason to keep it there except, it will keep rain water out, thus not cause my basement septic lift pump to run when we get the hard rains. So my question is: is there any safety, technical, or code reasons why I would want to remove this good neck. I realize some gas might linger in the goose neck , but with the flushing of toilets, and other heavy water use, plus atmospheric pressure changes, gases will still be vented out right?? I did put a heavy mesh screen at the end to keep curious birds out.
 
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Old 06-22-19, 04:38 PM
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The math in me says if it were to rain at 1"/hour (very heavy rain) for one hour you'd get maybe 2 cubic inches of water down the pipe. Doubt that would impact your pumping system to any extent.
 
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Old 06-22-19, 04:47 PM
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Tumble, yeah I am inclined to agree, but the pattern does seem to be there. The only other possibility is the check valve for this lift pump has a itty bitty leak in it. Time will tell. :-)
 
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Old 06-24-19, 09:51 AM
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To answer your original question, as far as I know, there's no technical or code reason that would forbid you from using two elbows at the top of your vent.
 
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Old 06-26-19, 01:37 PM
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Thank you sir. I'll ask for code around here.
 
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Old 06-26-19, 02:13 PM
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I've had two 90's on top of one of my plumbing vents for many years without trouble. I did cover the opening with fine hardware cloth to prevent insects and birds from building nests inside.
 
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