new pex supply line failure

chermann

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Why would a new pex supply line rupture? It was connected from the faucet to the shut off valve. The compression ring was in place and in the correct position and the nut was tightened with a wrench aprox, 3/4 of a turn passed hand tight. The line was attached with no leaks for about a week and then it separated. I am no stranger to these supply lines, but I have never had one separate on me before. Kinda at a loss. Any suggestions?!?!?!?!?
 
You said it was connected from the faucet to the shut off valve? The supply stop under the sink? Or did you have pex ran to the supply stop and then another material from the stop to the faucet?
 
It was the supply line from the shut off valve to the faucet. Its the grey semi rigid PEX tubing that I used here for the supply line instead of the braided supply line.
 
They are approved but I would never install one. Braided supplies under counters and rigid chrome in sight(if the homeowner wants).
 
Sounds like a gray PVC supply line permanently attached to the faucet??? A lot of models come that way now.. Just exactly what broke? Do you have a pic???
 
the PEX supply line is connected to the faucet with a nut. I used the plastic ferule that the line came with. I don't have a pic, but the line separated (pulled out) from the shut off valve even though the ferule and nut were in place properly and then tighened down.
 
you tightened the nut 3/4 of a full turn past what was hand tight to you? My guess was that the line wasn't long enough to fully insert into the valve, and the nut wasn't tight enough to compress the ferrule properly.

And even if it was done tight enough, an outer plastic ferrule compressing on a plastic supply line without an internal stiffener is not a proper way to make the connection. No wonder the line pulled out. There is a reason why plumbers prefer to use the braided lines, because they physically compress a tapered washer to make a lasting connection!
 
you tightened the nut 3/4 of a full turn past what was hand tight to you? My guess was that the line wasn't long enough to fully insert into the valve, and the nut wasn't tight enough to compress the ferrule properly.

And even if it was done tight enough, an outer plastic ferrule compressing on a plastic supply line without an internal stiffener is not a proper way to make the connection. No wonder the line pulled out. There is a reason why plumbers prefer to use the braided lines, because they physically compress a tapered washer to make a lasting connection!

I have never seen a poly supply line that had an insert that you speak of.....
 
connection

Poly/PEX lines do not COME with the stiffener insert, you buy them separately and use them. Without the insert tightening the nut may squeeze the tubing rather than compress the ferrule. In any case, I would never trust a "formula" such as "3/4 turn past hand tight" to make a permanent connection, after all, MY hand tight would be more or less than yours and which would be "correct" as a starting point? I tighten them as much as necessary to make sure they do not come loose. Normally that is a LOT more than 3/4 turn additional. That assumes I use them for faucet connections, which I NEVER do, but do use them for other purposes.
 
This thread got me to thinking. Three years ago when we bought our house a lot of the old vinyl supply hoses were bulging around the crimps. I replaced them with these Pex supply lines.

I bought them at the plumbing supply place in town. I asked the salesman if these were like an ice maker supply where you need the brass insert. He told me no and they don't even carry them.

I guess I better replace all of them now. I think if they were going to fail they would have in three years but who knows for sure. I would rather be safe than sorry.
 
I'm still not sure of the situation that failed. Was it a pex line installed with a rubber cone? Could you post a picture of what failed? Or examples of what failed?
 
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