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Eek - my copper pipes have melted away!

Discussion in 'Plumbing and Central Heating' started by SnakeyB, 25 Sep 2021.

  1. SnakeyB

    SnakeyB

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    Not exactly, but it would seem that knocking over a bottle of toilet cleaner (key ingredient: 9% hydrochloric acid) at the back of your under-sink cupboard without realising you've done it is a bit of a disaster for any central heating pipes that might have been running along the wall at the bottom.

    It's not along a massive length of the pipe, but it has totally wrecked where it has hit it. I can't immediately post a photo, but imagine lots of blue-green gunk covering the two pipes (along a length of about three inches), and great gaping holes (about an inch) in each pipe in the middle of that gunk, as if the pipe has been eaten away with only about a third of the circumference still intact.

    This actually happened a week or two ago so I have no idea how much water came out as there's nothing there now, but unsurprisingly, my boiler is at zero pressure and flashes red when I turn it on at the wall.

    My DIY skills stop at replacing lightbulbs, and I don't have any plumber recommendations so I'm more or less going to have to get somebody out of the phone book. I am hoping you nice people on here might help me understand what to expect, in terms of work required and how long it might take, so that I don't end up having someone take advantage of my ignorance.

    Specifically:
    1. There was no heating on at the time (the boiler was turned off at the wall) so nothing should have been circulating around the pipes. Does this mean the chemical damage is confined to more or less what I can see i.e. about a three-inch length of pipe, and not the rest of the system, the rads or the boiler?
    2. Is it possible to replace literally just a short length of pipe by cutting it and welding in a new section, or does the whole length need to come out as far as wherever the nearest existing join or bend is on each side?
    3. I assume "draining the system" has already happened via the holes in the pipes... might this have caused damage to the rest of the pipes and the radiators, since presumably that's all full of air now? Is it going to need power flushes and suchlike, or does it just get filled back up at the end of the repair work and the system carries on happily as before?
    4. There are three other copper pipes running under there (hot water to the bathroom, and hot and cold water to the washing machine). Luckily they were not directly under the spillage and while they have a bit of blue/green stuff on them in the same place - so they did get splashed a bit - they are not leaking. If these are OK now, does this mean they are OK full stop or would I need to replace them just in case it's still busy eating its way through and it'll get there in the end?

    Pending me finding a plumber etc, should I attempt to clean this stuff off the non-leaking pipes, or just leave them be?

    Thanks so much if you've read this far!
     
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  3. ianmcd

    ianmcd

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    most likely verdigris, fitter used too much flux and never cleaned it up after
     
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  4. JohnD

    JohnD

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    if there are actual holes in the pipes, as I understand you to say, but nothing is leaking out of those holes, those pipes must be disused.

    If there are not actual holes, clean the pipes with a green nylon pan scourer and water, and rub off with a coarse cotton rag. The advantage of polishing up the pipes is that it will remove old marks of corrosion, including the fitter's flux; so if any new appears, you can see where the problem is (for example a slight leak)

    Either way, please post some photos.
     
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  5. terryplumb

    terryplumb

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    Post some pics please. If these pipes are water pipes you would have had a flood ,did you ??
     
  6. SnakeyB

    SnakeyB

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    pipes2.jpg
    pipes.jpg

    In the top picture the top two pipes look massive because they are closer to the camera. I can trace them to the supply to the hot and cold taps so I think they are for the washing machine (which weirdly has both hot and cold feed pipes although it only takes from the cold).

    The "why aren't you ankle-deep in radiator water?" position is slightly complicated because I can't swear to how long ago this happened (I don't often have my shower at home, and have also been away). I would have thought that if there'd been a flood my downstairs neighbour would have had something to say about it, but like you say I don't see how this could have happened in a water-less manner unless I have a magic boiler or something! The pipes with the holes in are absolutely, definitely, 100% the same "pair of parallel pipes held to the wall by white plastic things" that I see running all around my flat joining the radiators together (sorry if that sounds like I'm being obnoxious, I don't mean to).

    All I can think of is that firstly the central heating heads out in two directions from the boiler (which is about three feet from these pipes) with the main rooms being on the other side, and secondly when you follow the pipes past these holes they go up and over my front door and back down again before running along to the remaining rads in the hallway and bathroom. So perhaps only one smallish section of the system water drained out through the holes, rather than the whole lot? I freely admit to not understanding how this all works. Alternatively, there is an ongoing intermittent leak that comes all the way from the top floor down through everybody's kitchen cupboard so I guess it's conceivable that - although it's not the same location - water did come from my kitchen into the downstairs flat but I "got away with it" because they thought it was that.

    But I swear the above photo is of the pipes under my kitchen sink and also that my boiler pressure is zero and it flashes a warning when I turn on the power, so something has definitely happened! Any ideas for how to sort it would be much appreciated.
     
  7. terryplumb

    terryplumb

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    That's a huge amount of corrosion ,and hard to accept it was caused by a toilet cleaner chemical being spilt onto them.
    If they are part of your current plumbing system ,sections need cutting out and replacing.
     
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  8. JohnD

    JohnD

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  9. flameport

    flameport

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    Which specific toilet cleaner was it?
     
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  11. SnakeyB

    SnakeyB

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    The nearly-empty bottle on its side at the back, which I assume was the culprit, is "Harpic Power Plus". If it's not that, I am at a loss to what else it could have been! These pipes are directly below my kitchen sink.
     
  12. flameport

    flameport

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  13. CBW

    CBW

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    Leaking boiler condensate pipe perhaps?
     
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  14. SnakeyB

    SnakeyB

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    So not a massive job then, despite how horrendous it looks? Just slice a foot or so out and replace, then refill the system and we're all good to go? That's a huge relief. I was thinking all sorts of things about how the whole thing would be wrecked etc.

    What do you reckon about the pipe below it, which takes hot water to my bathroom? It does not leak, but should I get that section replaced too just in case the stuff all over it hasn't finished doing its thing? Or should I get the scouring pad out as suggested upthread and see if it looks OK underneath? (Obviously I do not want to risk doing anything that might damage that pipe without a plumber standing right next to me, as it would presumably flood and flood until the whole reservoir is dry.)
     
  15. terryplumb

    terryplumb

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    Have that replaced also. What condition are the pipes either side of the areas in your pics ?
     
  16. SnakeyB

    SnakeyB

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    They look OK as far as I'm any judge.
    pipes3.jpg

    The central heating pipes are "mine" in the sense that I had the old microbore pipes replaced when I moved in, which is seven years ago now. Everything else has always been there. They are fine everywhere else around the flat (OK some of it is boxed in, but the bits I can see are fine).

    I was brave enough just now to wipe at the left-hand green bits (the smaller area you can see on here which was not included in my earlier photos) with a tea towel, and it was basically a ring of dried stuff that came right off - copper underneath looks fine as far as I can tell. It seems to have run along the top pipe from the main disaster area and dripped downwards at that point, perhaps. Still, I guess it's close enough to replace that bit as well without it doubling the cost/work.

    Having you guys to talk to makes me feel a lot better about this! I might even get the scourer out later and see if I can work out whether the bottom pipe (hot water) is intact vs a bit corroded. Like I said it's not leaking, but I don't want to take a chance if it might do in the near future.
     
  17. terryplumb

    terryplumb

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    I don't like the look of that bottom pipe ,Is it under mains pressure hot water ?
    Given the level of damage to the pipes above ,and the obvious contamination on the bottom pipe ,it could be a whisker away from bursting.
    Do you have a Combi boiler ?
    If I were you I would close the mains cold water stopcock ,open hot and cold taps to drain out / reduce pressure and get a plumber in.
     
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