Plan to fix PVC threaded joint leak

[ajw22]

I think you will end up needing to buy a new schedule 40 union, removing the old, and gluing in a new one.

Or forget the union and just use a coupler and glue the pipe together. Then put in a better pump union next time you replace the pump.

 

[wireform]

The whole install back to the pump looks hack. I'd go with post #2 if room allows the clearance for the other pipe and go up from there with a piece of pipe and coupling.

 

[TinFoilHat]

In my view, the pipe isn't even plumb so that could be why it began to leak in the first place.

 

[BullishBear]

Thanks yes did not find what I was looking for. Btw here is the dismantled pipe. Looks like there is O-ring stuffed within the pipe.

 

[BullishBear]

Looks like there is O-ring (rectangle cross section) stuffed within the pipe.

 

[JamesW]

It is old and deformed.

Just get a new O-ring.

 

[JamesW]

Measure the Inside Diameter (I.D), Outside Diameter (O.D) and Cross-Section (C.S).

ID + 2 CS = OD.

CS = (OD - ID)/2.

Enter the values into the calculator to find the O-ring size and order by size.

See example below.

AS568 O-Ring Size Chart - Marco Rubber

Interactive standard o-ring size chart to find Parker and AS568 o-ring size dimensions. Order Online millions of o-ring sizes are in-stock

www.marcorubber.com

 

[JamesW]

 

[BullishBear]

@JamesW You are awesome. Thanks! It’s 2 1/2" x 2 1/4" ID x 1/8" CS square (cross sectional shape) o-ring. Can it square (internet says, they exist and are called square rings) or they are circular but got deformed over the years?

 

[JamesW]

Looks like a Size #228.

The O-ring was originally round, but it got deformed from the pressure.

 

[JamesW]

 

[JamesW]

O-Rings - Further Reading

www.troublefreepool.com

 

[JamesW]

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[BullishBear]

TFP is a registered 501(c)3 non-profit that is maintained by user donations.

The people who answer questions are volunteers.

If you find the site to be a good resource, please consider making a donation to help support the site.

Thanks.

Become a TFP Supporter

Help Support TFP Trouble Free Pool is run by a dedicated group of volunteers that … Read more…

www.troublefreepool.com

For sure

 

[BullishBear]

Thank you @JamesW and everyone who chimed in. Replaced the oring (#228) and applied teflon tape, fixed the leak for good! Got some backup O-rings as well.

 

[JamesW]

You should not use Teflon tape on union threads.

 

[ajw22]

You should not use Teflon tape on union threads.

PVC Repair - Further Reading

www.troublefreepool.com

The "Do's and Don'ts" of Assembling Threaded Plastic Fittings from Lasco Fittings, now Westlake Pipe & Fittings, provided a great explanation of the Do’s and Don’ts not to have threaded fittings cracK.

 

[JamesW]

For a union, the O-ring provides the seal.

The threads only serve to provide the necessary compression of the two parts.

 

[Bperry]

Thank you @JamesW and everyone who chimed in. Replaced the oring (#228) and applied teflon tape, fixed the leak for good! Got some backup O-rings as well.

Probably remove the tape as the extra stress can crack those unions.

 

[BullishBear]

Wow, TIL! Thanks for the PVC Repair link! I have removed the Teflon tape from the threads. Just confirming my understanding, based on your comments & article, the reason for not using Teflon tap is that it may become easier to over-tighten when Teflon tape is present? The over-tightened state with pump's vibration may lead to cracks in union or deformation of O-rings, I presume? Thanks again guys.