Correction: I meant to say that it slipped out of the compression "nut".

"compression 'nut'"

Sounds like a defective install.
PEX normally uses compression rings to attach to fittings.

homebound,

Brickeyee is on the point. ALL "PEX" piping uses some sort of Barb fitting with a compression ring. I have never ever heard of a single failure with this type system. Compression fittings use a ferrule either brass or plastic. The brass ferrule bites into the pipe wall, but the plastic ferrule does not. It is not a surprise to me that a "Compression fitting" which has a plastic ferrule failed. All domestic water plumbing systems are required by code to be pressure tested, which may have revealed this issue. Was the system tested?

Dan

Compression fitting on flexible line (plastic) normally have a metal insert for the line that give the line enough strength to stand up to the compression force generated as the fitting is tightened.

Sorry, but maybe I'm totally botching the terminology here.

These are the plastic supplies from faucet body to the angle stop, typically cut to fit (similar to copper tubing back in the day). (Is that pex or just some other plastic supply? They are typically found in the stores along with the braided supply lines, etc.)) Each is sold with a plastic/nylon ferrule, which presumably is used under the nut when connecting to the angle stop. Right? And please reconfirm if the metal inserts are used with those types of plastic supplies. Thanks again for your help in understanding this.

BTW, the builder apparently is going to rip out a lot of new hardwood and drywall below due to this fiasco.

PEW is the plastic plumbing in the walls. The little plastic supply line from the shutoff to the faucet is not PEX.

In my old house, we had one of those compression fittings on the toilet supply line blow when we were out of town for the day. We had lived in the house for several years and hadn't had any problems. It had the metal insert, but it didn't matter. It ran all weekend and cause about $6,000 in damage.

Coming full circle, here.

It turns out they are, in fact, "pex risers" (check out google). They come in light grey or white. While they are sold with a nylon ferrule, one is also supposed to use a metal insert (stainless steel or brass) which makes you wonder why the insert doesn't just come with it, too.

Here is a link that might be useful: Pex riser

I had this happen just tonight. Luckily for us, we were home. The tubing just blasted right out of the compression nut. Don't yet know why, if I didn't tighten it enough or what. There was no damage to the ferrule, so not having the metal insert didn't have anything to do with it.

Thats why you spend (or have the builder spend) the extra $4 and install the braided hose which have deep threaded compression fittings.

http://www.homedepot.com/Plumbing-Bathroom-Faucets/h_d1/N-5yc1vZbreo/R-100056596/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

The reason they don't:
$1.48 for the plastic rise vs. $5.28 for the braided hose

The polymer braided hoses are not much better than the pex riser.

If you want to know it won't leak then use a copper riser instead of the pex one or use REAL stainless steel braided hoses which are much harder to find and more expensive.

Even the stainless steel braid lines are at best a false sense of security. While it is true that the stainless steel braid will prevent the line from rupturing from excessive pressure, ask yourself, what is the likelihood that the pressure in your house would ever even reach the blowout pressure for the line? Under that impressive looking stainless steel braid, most of those lines have a simple neoprene or polyehtelene hose. Now it is true that they offer a 10yr warranty, but then that is about the expected lifespan of neoprene hose anyway.

On the other hand, you can get a straight length of chrome, nickle, polished copper or gold plated brass supply tubing for about $3. The compression ferrule for the bottom end comes pre-packed in the angle stop compression fitting, and even if you are replacing a line and need to purchase a new ferrule, they are only a nickle.

The cone washer and brass friction washer for the faucett connection come pre-packed in the faucett set and most ppl just throw them away.

The down side is that you will need a tubing cutter to cut the line to length, but then no real plumber is properly dressed in the morning until he/she has their mini-cutter in their pocket and the cutter should be mandatory in any homeowners tool kit.

I will admit that when using the brass tubing you often have to bend it to fit but if that is the case you can get the beaded type line, which looks like a string of pearls and can be hand bent without tools, or you can get an in-expensive tubing bender and keep it in your tool box for future use. (You can often find an inexpensive tube bender on the el cheapo tool table at your local autoparts store for under $3).

The upside is that while the braided line has a 10yr warranty, if you install the brass line it will still be working fine when your unborn grandchildren are retired.

Ask yourself this question, if those braided lines were as good as some seem to think, why are they prohibited in commercial plumbing?

I don't think the complaint is that the tubing blows out. I guess that is possible, but unlikely. The complaint is that the compression fitting fails. When it fails - oh boy, does it fail.

When installed properly the compression fittings are every bit as reliable as a threaded fitting.

I too have experienced a pex supply line slipping out of the connection nut. Two weeks after a bathroom remodel we woke in the middle of the night to find water everywhere. End result ~$40000 of repairs and two months out of the house. It appears the plumber didn't sufficiently tighten the connection nut (once the connection nut was detached the plastic ring could slide up and down the pipe freely and would drop off if allowed).

I came here as part of an attempt to establish whether I should have a plumber re-install pex or use braided lines - one plumber says always use braided, another says pex are excellent and braided have their own problems.

The cheap braided lines at the box stores are not what consumers think they are. They are merely vinyl lines with vinyl braid and a clear sheath. They are not the Aeroquip SS lines that appear on race car brake systems and seen in high pressure hydraulic environments. IMO they are not as reliable as a copper line with fittings.

I'd ask the plumbers whether they have Pex or braided lines in their own homes and their parent's homes and hope for an honest answer.

Clearly the problem was installation. Compression fittings with ferrules require a certain "feel" to know when they're right. Are there any among us who hasn't messed one up and had to do it over? They're inexpensive and they do, indeed, work quite reliably when installed properly.....but they certainly are easier to make mistakes with, as apparently happened here.

Braided lines with screw-and-gasket seals are easier to get right the first time but, as stated, they, too, can have their issues. Must say, though, that I've personally never messed one of those up and I've never had one fail.

I've seen quite a few pacific rim cheapie braided lines puke and always where the fitting is crimped on to the outer braid. Failure is a tiny dribble followed up by a flood.

When it comes to compression fittings on Pex, copper, or anything else, it is the same as any other job... all you need is the knowledge and the tools. Lacking either invites less than a satisfactory outcome.

That's one danger when making professional tools available to the novice... they don't come with the knowledge on how to correctly use them.

When pros pooch a fitting they are responsible for the damage and that's why they are licensed and bonded but if you hired a handyman (woman) or did it yourself there's no one else to blame.

Pex is neat stuff till rodents chew though it ;-)

"Failure is a tiny dribble followed up by a flood."

I suspect there are likely many here who know exactly what you mean!

Posted by lazypup on Tue, Jul 5, 11 at 18:40:

"When installed properly the compression fittings are every bit as reliable as a threaded fitting."

What is the proper torque, or "additional turns after hand-tight", for 3/8" Pex riser with plastic ferrule? Been searching the internet for over an hour and can't find a spec anywhere.

This just happened to us in our master bath on the top floor of our 6 month old house. It is a Delta Trinsic Sink Faucet. Failure on the hot water side. Luckily we were home, but still tons of damage all the way to the basement. From what I've read on the thread it seems to be a installation issue. Does swapping out the pex for a braided line make sense or does the plumber just need to double check and tighten the fittings? We have pex tubing in all of our sink fixtures. Nervous that this could happen again while we are away...

Any line you use is only as reliable as its installer. A plumber that can't be bothered to install a PEX line correctly won't be bothered to install any other line properly. Fittings have specs for a reason - if those aren't followed, connections fail.

Happens all the time, if the ferrule came off the fitting, it was not tight enough, period. Time frame is about right, months is nothing, years, then I would wonder and, if the contractor is looking around saying, never heard of that happening before he/she is living in a cocoon.

What about if the fitting has been together for a year and a half without a problem? We had a tube blast right out of the compression fitting, after working fine for a year and a half. What would cause this?

Pex/Brass compression? hot/cold? what is basically boils down to is if it came apart it's highly likely it was not connected properly...... the time frame is typical...if you said after 5 years then I would wonder...

My home is 15 years old. I always turn the water off where it comes into the house when on vacation. 2 years ago we came back from vacation and turned the water on. Hours later we heard the pex supply line come loose with the sound of water spraying. We were able to clean it up quickly with minimal damage. The nylon ferrule was still in the shut off. The pipe was plenty long enough. Wrote it off as a freak accident. Now we had the same thing happen in an upstairs bathroom. More damage but luckily we were home.

I have a unit in a high rise condominium which has banned the use of plastic tubing to a compression fitting from a fixture to the fixture stop value. I imagine it is because of incidents like I have experienced with a 3 story house (described below). Particularly insidious is the tendency to develop a very small leak which isn't detected in the room where the fixture is located because it is too small and leaks into the wall cavity causing damages far removed from the source of the leak which make it hard to locate the source.

I am in the processing of cleaning up the mess from a long continuing and until recently not discovered leak from one of these connections from a sink fixture (hot water side) on the 3rd floor of a 3 story house with basement. Apparently for years, there was a slow drop, too slow and limited to be noticed as the water just seeped into the wall behind the fixture. On the first floor there was a bulge in the wall (interior) below the indoor unit of a mini-split system install near the ceiling, so some evidence of water where it shouldn't be, but, I suspect the lines from the mini-system and it didn't seem worth tearing open the wall to investigate.

Over time (years) the leak seems to have increased and I found water accumulated in the basement floor (concrete) near where the boilers, hot water heater and water softener were located. I suspected first the hot water heater (so shut if off at the water inlet), then the water softener discharge as the floor drain had blocked. The water heater was turned back on. Possibly the surge of water in the lines (as often happens when water has been off for a long time) may have cause a water hammer effect which increased the leakage.

In the end, I with a second floor ceiling collapsed exposing the underside of the third floor, I could see that it was a plumbing leak. It still took some time to find the bathroom (there were two above the ceiling with the problem because there was never a trace of water on the bathroom floor. All the water had leaked into the back of the cabinet at the seam between the cabinet bottom shelf and the cabinet back wall and from there into the wall.

That was the most troublesome thing about the leak. It just wasn't noticeable until the ceiling collapsed. The most obvious suspect, the mini-split system located just above where the damage was initially evident had nothing at all to do with the leak.