Slow leak from shower p-trap during leak test

[Temp945]

Hi all,

Thanks to the kind members of this forum I was able to pass my drain leak test (hydrostatic test) this morning!

However, after the inspector left, I noticed a tiny, slow leak at the shower p-trap swivel nut. I have attached a photo which shows the fitting and some drips of water coming out.

I double-checked and everything appears aligned correctly so i don't think that is the reason for the leak.

The nut that this is leaking from does not have a beveled washer - it is just a PVC to PVC connection. This is the trap that I used:

https://www.supplyhouse.com/Spears-...Trap-w-Plastic-Nut#pr-header-back-to-top-link

I did NOT use any thread sealant on this connection because I thought it would be classified as a compression fitting instead of a threaded fitting. I also only tightened the nut "hand tight" and also used a pair of pliers to snug it just a bit more. I would not be able to tighten it more (and not gouge up the fitting) unless I get a special wrench designed for the purpose.

How should I fix this leak? Here are my ideas:
- get a 3-way plumbers wrench to tighten the connection more:
https://www.homedepot.com/p/Husky-3-Way-Plumbers-Wrench-16PL0142/304217591
- use a PVC thread sealant on the threads:
https://www.homedepot.com/p/RectorSeal-T-Plus-2-in-4-oz-Teflon-Pipe-Thread-Sealant-23631/100201204
- use thread sealant and then tighten with the wrench

I don't want to over-tighten and break the fitting which I why I'm hesitating to do any of the above until I hear from people that know more than myself! Thanks for reading!

 

[Reach4]

https://www.homedepot.com/p/RectorSeal-T-Plus-2-in-4-oz-Teflon-Pipe-Thread-Sealant-23631/100201204
- use thread sealant and then tighten with the wrench

I would use a plastic-safe compound, and I think that qualifies. The compound adds some gap filling, but it also lubricates. So you can tighten tighter by hand than you can dry. So the wrench would probably not be needed unless the nut was awkward to reach.

You might as well go for 1.75 oz because I don't know that you can rely on that to stay good for years and years in the container.

 

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[Temp945]

Thanks, Reach4

Since it acts as a lubricant, is there a risk of over-tightening if I put the thread sealant on?

I'm hesitant to use thread sealant since this is not a threaded connection, but rather a compression fitting. I'm curious as to why this particular type of compression fitting is used at all instead of something that seals with a washer. The PVC to PVC compression fitting seems sloppy!

 

[Temp945]

I had the bright idea to call Spears technical support (manufacturer of the fitting). The gentleman was quite helpful and even retrieved the fitting so he could see it as we talked about it. He said that thread sealant was not necessary, but as long as it was safe for use with PVC, I could use it to help lubricate. He suggested using a strap wrench to tighten.

 

[Reach4]

Since it acts as a lubricant, is there a risk of over-tightening if I put the thread sealant on?

Yes. I think you could compensate by not using the wrench.

I'm curious as to why this particular type of compression fitting is used at all instead of something that seals with a washer. The PVC to PVC compression fitting seems sloppy!

I agree. I am not a pro. Some codes would have wanted you to use a glued trap, I think.

I wonder if contacting Spears would get some good info. https://www.spearsmfg.com/contact_information/contact_information.html Maybe ask SH.

Somebody may identify a more effective sealant for you.

 

[Jeff H Young]

no need buying a special wrench , plastic safe dope should work fine. iI would put some on threads and some on the male bevel. technically shouldn't need any thing. but we aren't harming anything with pipe dope that's compatible with PVC

 

[Temp945]

I applied some of the Rectorseal "T Plus 2" to the male threads and bevel and tightened it up. I then poured a 5-gallon bucket of water in the shower pan and no signs of a leak.

It may be that it would only leak under pressure, i.e., when I did the hydrostatic test overnight. I'm not going to fill the drains up again though to find out. I'll monitor it when we start using the shower again - but for now it looks good!

In the future I think I'll use solvent welded traps only. The swivel nut is just kind of lousy! Maybe its just assumed it will be under very little pressure?

Thanks everyone!

 

[Jeff H Young]

I only use that type p trap in 2 instances 1 they dont have all glue 2 the rare intance that I have a 2 inch trap for a sink and I may want to remove for cleaning. No big deal its just nothing to gain and a possible leak. I think its all good now!