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  1. #1
    Join Date
    Feb 2013
    Posts
    5

    Pex Tubing Rupture

    Hello everyone, first time here and I hope someone can help me with some information.

    In my home I have a hot water heating system powered by a Viessmann Vitodens 333 which is a gas fired condensing boiler. We added an living room extension onto the house 6 years ago and the heating contractor ran PEX tubing to three radiators that are embedded in the floor of the extension. For 6 years the system functioned without a problem.

    About 8 months ago we had a leak from the PEX tubing and after opening the floor we saw that it had a 4 cm split in it. The heating contractor who installed the system originally cut it out and spliced a new section into tubing. At the time he claimed that the material failure was due to the weather having been so cold for 2 weeks. I didn't buy the argument because there is hot water circulating through the system at all times, particularly when the temperature is under 0 C.

    Now, a leak has developed in different section of tubing in the same extension. They haven't opened it up yet but I'm sure it will be the same problem as with the first leak. Now, the same heating contractor is saying that the temperature from the Viessmann boiler is too hot, i.e., when the boiler must heat water there is a surge in the heating system and this weakens the PEX and therefore causes a leak.

    I'm sure you can understand my scepticism. I wish I could tell you more details about the type of tubing but all I have seen is that it is while, about 15-20 cm in diameter, and has an aluminum lining. By the way, we live in Switzerland if that helps.

    My question is, does this type of tubing rupture under normal operating conditions? And, if it does, what are the possible reasons for that happening.

    Paul

  2. #2
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,233
    http://www.ehow.com/about_6695610_pe...standards.html

    I might expect random, VERY Infrequent failures at joints due to installation Not material.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  3. #3
    Join Date
    Feb 2013
    Posts
    5
    I might expect random, VERY Infrequent failures at joints due to installation Not material.

    Any guesses on why these ruptures occurred?

    Paul

  4. #4
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,233
    Quote Originally Posted by paulbasel View Post
    Any guesses on why these ruptures occurred?

    Paul
    GUESS:
    http://www.ehow.com/how_5968750_crim...-properly.html

    An improper joint installation, does not have to leak at initial operation.
    I just saying the probabilities of a joint failure would be much higher than a material failure
    { given no scratches}.

    I would't term a joint leak, a rupture.
    It may be a rupture if you are applying > 100 psi when it's > 180'F
    or to a lesser degrees of pressure & temperature,
    IF the PEX surface was scratched.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  5. #5
    Join Date
    Feb 2013
    Posts
    5
    Dan, thanks for the explanation. I looked at the ehow link but that page shows how to crimp Pex joints properly. All of my joints are done with brass fittings.

    The failure was not at a joint it was a 4 cm tear or rupture in the PEX tubing itself. I examined the section he cut out of the first leak and there didn't appear to be any scratches on it. It just split wide open or to me it looks like a rupture.

    Paul

  6. #6
    Join Date
    Jul 2000
    Location
    Northern Wisconsin
    Posts
    1,974
    Finding out who the manufacturer is and what product of theirs that it is would be the first step. Most pex is marked along it's length that will give all this information along with it's specifications and to what standards it was tested to.

    All tubing (that should be used by a contractor) should have specific ratings as to how much temperature it can take at a specific pressure. "Most" heating pex that I've seen is rated at 100psi @ 180F.

    If your contractor is pointing the finger at the boiler or other issues like the outside temperature as the reason for the tubing failing, it still (in my opinion) is their responsibility because they installed it. If they did so without taking into consideration what kind of operating conditions it could be subjected to....... shame on them.

    Splits in the length of the tubing is "normally" due to the fluid running through it exceeding the maximum pressure and temperatures that it was designed to operate at. The other reason in this type of tubing is due to freezing.

    If your contractor is not going to stand behind his original installation and product choice it might be time to call in a second opinion. Manufacturer's have warranties on their products, but you'll need to know what you're dealing with. I would suggest that you not let the contractor take the failed section of tubing with them when the repair is done. It is your only proof of the failure and what type of failure it was.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  7. #7
    Join Date
    Feb 2013
    Posts
    5
    Thanks for the solid info and advice. All of the tubing is hidden from view so I really can't see any markings on it, but I will retain the failed section and try to find the manufacturer. I'm not sure about calling in another heating contractor. Don't they just cover up for a colleague in the trade. In Switzerland we have technical expert ombudsmen who for a fee, of course, will adjudicate a disagreement between tradesmen and the home owner. Maybe I'll go that route.

    Paul

  8. #8
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,588
    Can you show us a picture of the broken piece, we may be able to figure out what type it is.

  9. #9
    Join Date
    Feb 2013
    Posts
    5
    The repair will take place this coming Friday. I'll post a picture of it after that.

  10. #10
    Join Date
    Feb 2008
    Location
    Altmar, New York, United States
    Posts
    4,252
    pipes can freeze even if it is pumping hot water providing the temps are cold enough and wind leaks on to the pipe. most pex has a high temp rating and is unlikely to just split away from a joint for no reson. what is the boiler heating temp set at?

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