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Pex connections failing

25K views 16 replies 7 participants last post by  Termite 
#1 ·
I have a large home that I believe has PEX piping (the home is only two years old). Twice (once under the house and once under the bathroom sink) a connection failed and the plastic pipe shot off of the copper fitting. Catastrophe was avoided both times because we were at home.

Now the home is vacant, to be rented out. Are these failures caused by high water pressure? (the house has a hot water recirculation system that could be a factor). I plan to check the pressure with a water pressure gauge. Any
other suggestions?
 
#2 ·
Is this freeze related? I wonder what kind of fittings were used? Any chance of you posting a picture?

And not for nothing but three in less than two years, Im shutting off the water, draining the pipes and calling a pro to come in and check it out. So far Ive tried three different types of Pex fittings and like only one.

Some crimp fittings IMHO, are garbage, some are better.
 
#4 ·
There are no copper pex fittings, there are plastic or brass, you probrably have brass. As for under the slab leaks, there should be no connection under the slab because the copper crimp rings are not rated for instalation in dirt(unless you ment you have a crawl space), if there are fitings under the dirt they should not have been there. The tool plumbers use (a crimper) has to be calabrated to ensure a complete crimp of the ring, after many uses the crimpers tend to lose its calabration, its a quick fix for the crimpers, but not for your house. There is a calabrater they sell(very cheap) to check if the rings are being crimped full, one side has slots for "GO"wich means the rings are fine or slots with "NO GO", wich means the crimper is not calabrated correctly, its a simple tool, you simply try to slide the slots over the ring that are on the pipe , if it slides over the ring the ring is fully compressed over the barbs on the fitting. I would buy this tool and check as many fittings that are exposed.
 
#6 ·
Right, the beauty of pex is the ability to use less fittings, there should be some exposed, like the supply lines might have a crimped pipe at the shut off valve, unless they stubed out with copper. Or the supply to the heater, if these locations do have crimped fittings I would check there
 
#7 ·
Sorry - I failed to mention that the house is off grade, the leak underneath
was easy to fix. I'm not at the house to look at the piping right now- but I know the fitting under the house was brass. I don't recall any type of crimp ring. Do all Pex systems use crimp rings?
The water is shut off right now due to the house being vacant. I didn't drain the system - furnace is on and under the house, so should be OK.

The problem is definitely not freeze related, happened in the summer.
 
#8 ·
There is one system that uses an expanding tool and a collar also made out of pex that simply stretches over the fittings. Since pex has memory, it supposedly keeps a tight connection. I don't know, I think I would rather use a cinch clamp or crimp ring system.
 
#9 · (Edited)
There is one system that uses an expanding tool and a collar also made out of pex that simply stretches over the fittings.
Thats system uses the everloc and slides a brass ring over the expanded pex. Huge advantage to this system is that the fittings are true to the size of the pipe. The typical pex fitting reduces the size of the pipe at the fitting by about 1/3rd. add on the 90's and want not and you have restricted flow and volume.
 

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#13 ·
Here's a picture of the aforementioned expansion PEX fitting. A tool is inserted into the tubing that expands it and allows for insertion of the fitting. The tubing's memory causes it to grab the barb very hard. Awesome setup, but less common due to the cost of the tool and fittings. The crimp-type are much more common, and in my opinion are just as solid. I've installed a heck of a lot of PEX and have 100% faith in the product.
 
#14 · (Edited)
All the connections under the house are definitely the system pictured above, except the fitting the pex goes on is brass.
I don't recall the connection under the sink looking like that but will check today.

How should I , or the plumber, check for proper work on this type fitting? I assume a "Go, no go" tool won't work.
 
#16 ·
I'm pretty sure there are no pex fitings or connection that use ferrels, I've only worked with crimp rings, and have seen a demonstration on the memory pex, are you sure it is a ferrell and not a crimp ring, the ring would look just like it sounds, and about 1/4 " in width, the ring is copper but would look darker, almost black.
 
#17 ·
I've never seen any sort of PEX that uses ferrules or any sort of threaded/compression connection.

Would you be able to post a picture of this?

For an easy DIYer-friendly tool-less fix, take a look at the "Sharkbite" fittings. They're great for PEX as long as the connections are accessible.
 
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