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Discuss Burst plastic piping. in the Central Heating Forum area at UKPlumbersForums.co.uk.

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  1. Martin Dunne

    Martin Dunne New Member

    Hi all,

    I have a recurring problem with my central heating system, the pipework from my boiler to the hot water tank keeps on bursting, it has occurred 3 times now. The pipe is 28mm Hep2o and it is physically splitting the pipe, not blowing off at the fittings.

    The house is 9 years old and this is the 3rd time it has happened, always on the same piece of pipework, should there be some pressure relief to prevent the pipe from bursting as when it bursts it pretty much explodes.

    Does anyone have an idea as to what the issue could be? Is it a defective peice of pipe or is there a fundamental problem with the system?
     
  2. Ric2013

    Ric2013 Plumber Top Contributor!!

    How close to the boiler is the pipe? In terms of metres or feet of pipe run.
     
  3. Martin Dunne

    Martin Dunne New Member

    The closest the pipe has burst is approx 4 metres from the boiler, the furthest is about 7 metres.
     
  4. Ric2013

    Ric2013 Plumber Top Contributor!!

    That isn't too close to the boiler.

    If this is a sealed system there should be a pressure release dump set at 3 Bar, often incorporated in the boiler. Hep should be good for 6 Bar even at 90°C...
     
    • Like Like x 1
  5. Martin Dunne

    Martin Dunne New Member

    Yes it is a sealed system. Boiler is an ideal isans.
     
  6. Martin Dunne

    Martin Dunne New Member

  7. oz-plumber

    oz-plumber Plumber

    If I were you, I would send the pics to the manufacturer of the pipe.

    I would go as far as requesting someone from the manufacturers to come and inspect the pipe.

    If this has happened on the same piece of pipe on 3 separate occasions, they will be interested in testing the pipe.
     
  8. Ric2013

    Ric2013 Plumber Top Contributor!!

    The same batch of pipe, or the same section within your installation?

    I wonder if the PRV is seized?
     
    • Like Like x 1
  9. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Wouldn't be in the same spot tho every time
     
  10. Ric2013

    Ric2013 Plumber Top Contributor!!

    Yeah, presumably the OP has bought a length and keeps using this batch to repair the damaged section?
     
  11. scott_d

    scott_d Plumber GSR

    Any rodent problems?
     
  12. rpm

    rpm Trusted Plumber Top Contributor!!

    No signs of teeth marks on that section of pipe.
     
  13. Martin Dunne

    Martin Dunne New Member

    The damaged pipe is the original pipework installed when the house was built. I have patched it twice now but obviously something is amiss.
     
  14. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    If you still have the split piece I would send it to the manufacturer and ask them to analyse it to see if they can pin point it
     
    • Agree Agree x 1
  15. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    Definitely get the manufacturer involved. You never know they may admit fault!!
     
  16. scott_d

    scott_d Plumber GSR

    Any pictures of the boiler? Could the pressure relief have been capped off or isolated?
     
    • Agree Agree x 1
  17. Chuck

    Chuck Active Member

    It could be a batch of faulty pipe, but I doubt it. Given the consistent way it's failing, it is more likely to be an incorrectly designed/installed system. The expansion vessel might, for example, be on the wrong side of a zone valve so it's isolated when you are just heating the HW tank. Numerous other possibilities. We need to see photos, please. Lots of photos.
     
  18. AWheating

    AWheating Trusted Plumber GSR

    Remove sction of pipe and pressurise to 20bar and see what happens. Go higher see what fails
     
  19. AWheating

    AWheating Trusted Plumber GSR

    Wet test tho, not air
     
    • Like Like x 1
  20. Martin Dunne

    Martin Dunne New Member

    I'll try and get some pictures added, working 12 hour shifts so haven't had time to do a great deal.

    Thanks for all the replys
     
  21. oz-plumber

    oz-plumber Plumber

    The only fault they will admit to is an installation fault!!!

    Excuses:
    - Never ever seen that with our product.
    - Our quality control systems wouldn't allow that to happen.
    - It must be due to damage in transit - we can't be held accountable.
    - Something has caused external damage to the pipe causing the pipe to rupture.
     
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    • Winner Winner x 1
  22. Martin Dunne

    Martin Dunne New Member

    Here are some photos of the system

    20170919_200843.jpg

    20170919_200853.jpg

    20170919_200900.jpg

    20170919_200912.jpg

    20170919_200917.jpg

    20170919_200924.jpg

    20170919_200937.jpg

    20170919_200949.jpg
     
  23. Martin Dunne

    Martin Dunne New Member

    And some more

    20170919_201047.jpg

    20170919_201052.jpg

    20170919_201127.jpg

    20170919_201132.jpg

    20170919_201146.jpg
     
  24. Martin Dunne

    Martin Dunne New Member

    Does it matter which side of the pump the PRV goes?
     
  25. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    For what ? You've already got one on the expansion vessel kit
     
  26. Martin Dunne

    Martin Dunne New Member

    Just wondered if it made a difference which side of the pump it was fitted to. Clutching at straws really as to what the problem is.
     
  27. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Apologies if this has been mentioned, I havent read all the comments but is that Hep ? , I cant see any print on the pipe.
     
  28. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Normally expansion vessel and prv on return
     
  29. Martin Dunne

    Martin Dunne New Member

    Yes it's hep2o
     
  30. Martin Dunne

    Martin Dunne New Member

    Ok, thanks.

    Any ideas where my problem lies?
     
  31. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    no sorry my best answer is to send a section that burst to the manufacture
     
  32. Ric2013

    Ric2013 Plumber Top Contributor!!

    Hmm. There are various PRVs on your system. I'm not familiar enough with this type of system to work out which one serves the section of pipe that is failing. At 60°C, 9 Bar is the limit, 7 Bar at 80°C, and I note one of those PRVs doesn't kick in until 9 Bar. And I'm suspecting one or more of those PRVs may not be working 100% correctly. Anyone think there is any mileage in this train of thought?
     
  33. zzzjim

    zzzjim Well-Known Member

    The flexi on the expansion vessel , made me think of a boiler prone to blockage in flexis . Not good on unvented !

    Was the split facing the same way as last one -below ?
    (seam fault /or scratched during instal ..! )
     
  34. Best

    Best Trusted Plumber

    I have seen that happening to plastic pipes on flow from oil boilers where the oil boiler was overheating.
    Yours is happening always on flow pipe, which points to overheat.
    The barrier pipe has 2 walls and breaks down (basically melts) when overheated, goes paper thin and splits.
    I don't know if it is possible a gas boiler could also overheat, but I guess it could.
    Is the heat in the pipes from the gas boiler extremely hot?
    The red expansion vessel (EV) is for your heating system and should be connected where it cannot be isolated from gas boiler. The vessel needs serviced each year to check it has correct air charge, but the PRV on it is supposed to keep heating system limit to 3 bar max should the EV fail. If it was a over pressure problem that would mean both the PRV and the red vessel are faulty. Personally I would also have a PRV off pipework close to boiler as good practice.
    Even if your PRV and red vessel were non functioning, it normally wouldn't cause your heating system to run with extreme pressure, but I would check the filling loop isn't passing mains water through into system and raising it to very high pressure.
    The hot water unvented unit and its valves are irrelevant if it is definitely a heating system flow pipe bursting, as they are to do with mains hot water - the red vessel with its PRV, filling loop and gauge are the heating parts to have checked.
     
    Last edited: Oct 1, 2017
  35. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    I would employ the services of a G3 engineer and replace all the saftey valves and both expansion vessels on the system it is looking a little tired and could do with some tlc, the expansion vessel on the cylinder needs supporting better than it is when they fail they weigh quite alot, i have had over heating on the hotwater side of these cyliders the thermostat pocket is quite large which the stat bulb slides into which allows the water temp to creep higher than it possibly should it needs to be measured and checked , set your boiler stat to 650c no higher and check this also . cheers kop
     
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