Plumbing Help - Connecting Water Shutoff Valve

[johngalt]

I installed my Greenfield ASV water shutoff valve which looks identical to the Elk WSV2.  It has 1" FNPT threads.  I want to connect it to my 3/4" PEX water supply line coming into the house.
 
I used a 1" MNPT to 3/4 PEX crimp brass adapter.  I used some white teflon tape and tightened it down extremely snuggly.  I still had a little leak.  I tightened it down a tiny bit more and the leak stopped, but I am nervous it is might leak in the future.  My guess is I need to use the yellow (high density) teflon tape, more white tape, or pipe dope.
 
Also, someone told me I didn't need to worry about a dielectric union because it was a PEX pipe despite the fact that I was joining stainless and copper.  
 
Any thoughts?

 

[42etus]

My guess is I need to use the yellow (high density) teflon tape, more white tape, or pipe dope.
 
I think any of the above will solve the leak issue. I know many swear by teflon tape, but I've never really liked it. Pipe dope, though messy sometimes, just seems to work better for me.
 
I can't speak to the need for a DI union. There's probably a ton of info on the net about it though.

 

[RAL]

I would say that no, you don't need a dielectric union in this case. But it has nothing to do with the PEX.  The reason is that the galvanic difference between copper and stainless steel isn't that large.  If it were galvanized steel to copper, then yes, you should use one.
 
One lesson that I have learned from my plumbing experiences is that pipe threads need to be tightened far more than you would think is reasonable to keep them from leaking.  I used a 12" wrench with a 12" piece of pipe as a cheater to tighten some 3/4" fittings sufficiently.  I thought I had them as tight as they would go without using the cheater to extend the handle, but they still leaked.  With the cheater, I was able to tighten them down another full revolution.
 
Yellow teflon tape might have helped a bit.  I've also found that PTFE thread sealant seems to work better than tape.

 

[johngalt]

Thanks.
 
I guess I have never tightened down a pipe with a 1" threads.  When I think about it a 14 inch wrench provides a lot more torque on a 3/8" size thread vs. 1".
 
Now that I determined I need to remove and reseal that connection with more/better sealant and torque, any recommendations to remove the PEX crimp rings.
 
I was planning on just cutting them with a dremel disc cutoff tool, but I suppose I could just cut the PEX and then splice in a short piece that I need to regain that length.

 

[RAL]

There are some PEX crimp ring cutting tools, but I think they require you cut the PEX tubing off at the fitting, so you can't avoid losing a bit of length on the tubing.  Not sure it would be worth buying one just for the two fittings you need to re-do.
 
If you are really careful with the Dremel, maybe you can cut almost all the way through the ring without damaging the tubing and then break the ring off.

 

[wkearney99]

14" wrench?  That's tiny.  When my father-in-law passed I nabbed a 36" monkey wrench from his shop (among other tools).  That and a pipe threading set with an equally long handle that'll cut up to 3" diameter pipe.  Being a substation electrician for the power company apparently requires some beastly torque on some threads...
 
The key with any plumbing is make sure you're keeping even pressure on both sides, or making sure one side is NOT moving.  
 
Me, I prefer to pay a plumber when it comes to water lines under constant pressure.  I want his insurance paying out when things go wrong...

 

[johngalt]

Me, I prefer to pay a plumber when it comes to water lines under constant pressure.  I want his insurance paying out when things go wrong...

 
Ha!  I would agree with you.  However, with the subcontractors I used to renovate my house I think "If you want something done right, do it yourself" is a better fit.

 

[kurtmccaslin]

I prefer to use a teflon pipe dope like Rectorseal.   I have had virtually 100% leak free connections with it.
 
Teflon tape works too, but you need to make the right number of wraps, and in the clockwise direction.   I dont use it enough to have the technique down.   Rectorseal is pretty foolproof.

 

[johngalt]

Thanks. I have never used pipe dope before, but it seems RectorSeal #5 is highly recommended from some searches online.

I will try that and tighten it down as snug as I can and give it a shot. Thanks.

 

[apostolakisl]

Galvanic difference:  http://www.engineersedge.com/galvanic_capatability.htm
 
If it isn't leaking, done.  Don't take it apart.  Especially if it is able to be inspected.  
 
Even if it leaked a micro amount, put a bucket under it and in a few days it will stop from mineral deposits.  I had a 1 inch union that I ended up doing that with after torquing it on with a 36" crescent wrench until I started to fear that I was going to tear the metal.  The micro drip stopped after a few days and that was 2 years ago.
 
36" pipe wrench's are for weenies.  You need a 48" to be a real man.   :mellow: (just to be clear- don't use a pipe wrench on those fittings, you'll bugger them all up)

 

[johngalt]

Thanks for the link. That was a lot simpler then other material I had found. It looks like stainless to brass under the house should be okay. Despite it being in the south with high humidity and less than a mile from the ocean.

I checked it tonight and there was just a wet spot the size of a silver dollar on the vapor barrier. I might give it a few days and see. If not I will take it apart and use RectorSeal #5....and I might need a bigger wrench.

 

[RAL]

With a small leak like that, it's worth waiting a few days or even a week to see if it cures itself.  Not likely that it will get worse.