50% of my 1/2" pex a connections leak

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essentials

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I am having only a 50% success rate in making 1/2" pex A connections that do not leak (out of 8 attempted connections). All the fittings are brass. I have a 100% success rate making 3/4" pex A connections that do not leak (on 10 connections, mostly brass). I would like to isolate the problem in my 1/2" process or materials so that I may fix it. I have a 100% success rate with sweating copper thus far... thought the pex was supposed to be easier!

Update: The VEVOR manual expander tool was the cause of the problem. The issue was that the fingers on the 1/2" head would slide around the cone, causing all the expansion to occur between a single pair of fingers. This would result in badly-stretched pipe. I suspect this is not a problem with other manual or automatic expanders. See my more detailed reply with photos of the problem further down in the thread.

I have run 4 1/2" pex A home runs for a shower and lavatory (each requiring a hot and cold). 3 out of the 4 connections at the manifold have slow dripping leaks. The connections at the fixtures are all good except for the hot lav connection, which has a somewhat faster dribble. The lav uses the 1/2" FIP fittings below while the shower uses the 1/2" sweat connections.

Materials and tools:​


The possible points of failure that I can think of are:​


• Rings or pipe are too cold to expand/contract properly​

The basement (where the manifolds live) might often be 55F or so. And the water inside the cold manifold is probably sucking some heat from the pipe once in contact. This might explain why most of the problems occur in the basement. Perhaps I need to warm the rings, pipe, and manifold before using the expansion tool?

• The brass fittings have nicks, grooves, etc​


The FIP and sweat fittings all came with protective plastic sleeves over the pex connector whereas the manifold heads had no such protection. 75% of the failures are on the manifold. The plastic sleeve on the one leaking FIP fitting was only removed seconds before being connected.

The Souix Chief manifold valve heads certainly do have imperfections if I look closely enough. They were delivered like this from pexuniverse.com. Take a look:

20240415_123505.jpg

Are the imperfections above serious enough to cause leaks? Would this be normal condition for a new valve? It isn't even possible for a flat surface (like the inside of a shipping box) to come into contact with that middle barb with the groove. Short of exchanging this product for an actually-new one, are there any hacks to get this sealed? Returning these would be a bit of a PITA since they were not purchased locally.

• I am not rotating the manual expansion tool the appropriate amount between expansions.​


I am rotating the tool somewhere between 20 and 60 degrees between expansions. I am not using anything to measure the exact amount of rotation, so the amount is somewhat haphazard. I generally try to make sure no two expansions take place at the very same angle.

• I am doing too many expansions​


I am doing somewhere between 5 and 8 expansions. I will generally do 2 or 3 expansions at full insertion.

• I am doing too few expansions​


I am doing somewhere between 5 and 8 expansions. I will generally do 2 or 3 expansions at full insertion.

• There is a reason this expansion tool is only $87​


This VEVOR tool is way cheaper than any others I have seen. Anyone ever used it with half inch successfully? Nobody in town rents the automatics and I'd rather not spend $500 to run an experiment with the DeWalt.

• I have defective pipe​

• I have defective rings​

• The pipe and rings are not compatible​


Should I try some SharkBite brand rings to go with the SharkBite pipe instead of the Sioux Chief rings? I got the Sioux Chief ones because they were cheaper. For the 10 flawless 3/4" connections, I used SharkBite brand everything--pipe, rings, fittings. Used the same expander tool (different head).

• I am not cutting the end squarely enough​


Seems square to me.

• I am not sliding the ring far enough onto the pipe.​


It's pushed all the way to the lip on the ring.

• I am sliding the pipe either too far or not far enough onto the fittings.​


Judge for yourself. The right one leaks (as you can see from the water on its face) the left one does not.
20240415_113155.jpg


• Pipe is dirty​


I did not take any action to clean the inside of the pipe. However, we are talking about fresh cuts in the middle of a 300ft length of pipe. I am assuming it came clean from the factory.

• Brass is dirty​


I used a clean cotton cloth (paint rag) to wipe off each fitting, except for the FIP ones where I removed the factory plastic sleeve seconds before sliding the pex over the fitting.

• Haven't waited long enough for the pex to contract​


It's been over 24 hours on one of the leaky connections, but more like 12 hours for the other 3. These are all indoors where the temperatures are somewhat reasonable, but the water in the manifolds can be pretty cold. Even the hot manifold has one leak though. I did try blasting one with a hair dryer for a few minutes without success.

The one non-leaky connection to the manifold is on the hot side, and it took several hours before it could be used without leaking. The 3 non-leaky connections at the fixtures also required at least an hour to seal. My understanding is that it is not normal to need to wait so long for pex A connections to seal. Does this suggest the pipe/rings/tool (usage) is more likely the culprit?

The 3/4" pex with one exception sealed within minutes.




Any recommendations for where I should go from here? I need to run about 10 more home runs, and I'd like to avoid repeating this pattern. And obviously I need to fix the existing leaks.

Diagnostics I might perform:​

• Keep the rings in my pocket for the rest of the day. Store the pipe in a warmer space. Drain the cold manifold of cold water. Then try running more lines.

• Run a short length of pipe connecting two valve heads together. Pressure test it. Record result. Remove the pipe. Repeat 10 times using the very same pair of valves. If a specific valve either fails or succeeds every time, then the problem is likely the valve head and not the tool/pipe. If it succeeds some times and not others, then the problem probably is not the valve head. Unfortunately, it seems like this might take a week if it takes hours for the pex to contract.

• Spend $500 for the dewalt kit to see if it works better.

• Experiment with doing more expansions or different rotations with the expansion tool. Again, quite time consuming since it has taken hours for these things to seal.

• Buy different rings and test whether things get better.

• Buy different pipe and test whether things get better.

• Buy different manifold and test whether things get better.
 
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Jeff H Young

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most inexpensive expanders dont rotate and can cause a leak if you dont rotate. my gut says warmer pipe and fittings might help , they say cold will contract back to normal I just am not real comfortable with the tempurature but only because you have issues. havent done much pex I was on one job for 4 monthes daily about 100 joints a day and havent touched it since in 8 or 9 years . we were giving it quite a few expansions Im guessing 6 or 8 with a milwaukee gun had a few leaks by nicking the barb ever so slightly when we had to cut a ring and pipe off to reuse the fitting.
No to be snobby but Im skeptical of every thing from that vevlor company. 4 leaks outta 8 joints is horribble and you darn sure are trying to do right make sure you are rotating and ample time befor water
 

Breplum

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We have the M12 Milwaukee tools (with rotating heads). Hundreds of joints with no leaks, mostly mild weather here.
We try to only use Uponor name brand fittings and pipe. That way Uponor can't wiggle out of liability in the future.
 

essentials

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Will be testing 18 new connections tomorrow.

FWIW, here are some images of the 1/2" head on this tool. The first image is the fully contracted state and the second image shows it fully expanded. The 1/2" head is... less symmetric than the larger ones.

20240417_004534.jpg

20240417_004843.jpg

20240416_231818.jpg


I am going to try pushing the spring around to get a little more symmetry.


Here is an autopsy with some sharpie for contrast:
20240417_001759.jpg

20240417_001158.jpg
 
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JohnCT

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I haven't done all that many expansions (amateur plumber - personal real estate work), but I've never had a leak. I use a Milwaukee expander and automatic expansion heads and have never used the manual expander. Additionally, I made about 6 expansions with Zurn B 1/2" on a small project as an experiment and they didn't leak either. In every case, I've only used the polysulfone fittings, never brass (acidic well water in my area).

I go 3 expansions once the head reaches full insertion to make sure it cleans up/evens out any ridges made when expanding. I've never seen a leak - I wait 10 minutes after last expansion to pressurize.

I honestly don't know how anyone can use a manual expander cleanly and properly without three arms. Honestly, if you're doing that many connections you should buy a power expansion tool or move over to crimp fittings.

John
 

essentials

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I found the smoking gun yesterday. In case anyone runs into this same problem, here is what was going on:

I happened to look at the VEVOR expansion tool from the side as it was expanding a pipe+sleeve. When expanding under load (i.e., with an actual pipe around it) all the fingers bunch up on one side of the cone and most of the expanding occurs between a single pair of fingers on the opposite side. So it ends up over-stretching one side of the pipe and leaving the rest alone. I took a photo expanding just a pipe without a sleeve so I could share it here (didn't want to waste a sleeve on you guys, sorry!).
20240418_202441.jpg


Compare the size of the gap in the top left ellipse with the size of the gap in the top right ellipse -- the right gap must be 5 times larger (this camera angle even makes it look smaller than it is). Observe the way the pipe material has deformed over the huge gap in the bottom right ellipse. As one part of the pipe begins to deform more than the rest, it becomes the weakest side of the pipe, meaning later expansions favor expanding that weak area even more.

I believe the problem is that the VEVOR tool has no grooves/tongues to ensure that the fingers can't just slip around the cone and expand whichever side of the pipe is the weakest. While I can use a screwdriver to try to equalize the gaps, the teeth just end up sliding back into the bad position after two expansions or so. Since I'm trying to follow the Uponor instructions (VEVOR tool's instructions are underspecified and written in broken English) about doing 4 expansions with 45 degree rotations for 1/2" pipe, 2 good expansions is not enough.

I picked up the DeWalt power tool and every connection has sealed within a couple minutes. On the DeWalt we can see these grooves on the back each finger that prevent this kind of incident:
20240419_131350.jpg

The VEVOR tool simply has a flat surface back here. If shopping for one of these tools (even a manual tool) I would make sure it has these grooves and matching tongues. I have returned the VEVOR tool to the store and intend to write a scathing review. What a waste of time and materials; the price was half that of the other manual expanders for a reason -- probably because they know it doesn't work.

I still have dozens of joints that were formed by trial and error using the VEVOR tool that are not leaking in practice. The big question is, do I proactively redo them all, or at least the ones in finished spaces? I have a feeling I know the right answer.

I absolve the Sioux Chief and SharkBite products from my OP of any wrongdoing.
 
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