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What likely caused this horrible corrosion on copper return from cast iron radiator?

Long story, there is 1 1/4 tee off hot water main which was reduced to 3/4 and run as copper to the LR radiator. No others are copper. I never looked close. Previous owner sheet rocked the basement den which hid this below until recently. I replaced all the valves when I moved it years ago but did not replace any return elbows.

The supply looks OK but the return is ugly. What metals am I looking at? Is this all copper until the return elbow? Yes I see the hairline crack. I will wait until summer if I can to replace the lines. This radiator and almost all are not valved off so if this leaks I am screwed.


https://i.imgur.com/lXpp1U1.jpg
https://i.imgur.com/s1KE2G8.jpg
https://i.imgur.com/Z4fitaV.jpg
Home owner near Minneapolis with cast iron radiators, one non working slant fin now ripped out, and hot water heat.

Comments

  • SlamDunk
    SlamDunk Member Posts: 1,555
    edited February 2023
    Intergranular corrosion between two different metals and water as an electrolite? Just a guess. Bad guess. Galvanic corrosion.
    Mad Dog_2
  • hot_rod
    hot_rod Member Posts: 21,799
    Looks like all threaded steel in the pic. Is the copper transition below the floor or inside that insulation?

    Or is that just years of pet hair?😳

    If there was a small seep keeping the insulation wet or damp, the corrosion could be from outside in.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Mad Dog_2mattmia2
  • eclecticmn
    eclecticmn Member Posts: 121
    What insulation? What material is the hairline crack in? I posted a close up photo below the floor that may show iron going to copper? What is the blue-green pipe going under the floor?
    https://i.imgur.com/wj2C37f.jpg

    Home owner near Minneapolis with cast iron radiators, one non working slant fin now ripped out, and hot water heat.
    Mad Dog_2
  • Jamie Hall
    Jamie Hall Member Posts: 22,878
    Looks to me like the cracked fitting is a sweat to thread fitting -- probably brass -- and the pipe below the floor is copper. And... the staining on that pipe indicates that that there has been long term leakage from the fitting -- probably in the threads. That, plus some stress, has caused the fitting to crack. It's not if there is a leak -- there is, and it's been there for quite a while. The question is when will the crack propagate to complete failure. It probably extends some with every heating cycle.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    eclecticmnMad Dog_2
  • Waher
    Waher Member Posts: 230
    edited February 2023
    I think that's biological growth (mycelium) and not pet hair. I think that is cracked and leaking which is causing the verdigris to follow the path of the moisture. If it isn't actively leaking now, it's because corrosion temporarily patched itself shut.

    I wouldn't wait to replace that. It needs immediate attention. You shouldn't even try to wrap that pipe with any of those emergency siliconized tapes because it might crumble worse if you touch it.
    reggieclecticmnMad Dog_2SuperTech
  • reggi
    reggi Member Posts: 494
    A zoom of your close up shows how close to failure this has progressed.... and the pet hair 
    One way to get familiar something you know nothing about is to ask a really smart person a really stupid question
    eclecticmn
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,183
    Maybe the pet hair is reinforcing the crack...
    eclecticmnMad Dog_2archibald tuttleSuperTech
  • hot_rod
    hot_rod Member Posts: 21,799
    Double glove for this repair😗 Maybe a mold respirator 
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    reggiMad Dog_2
  • reggi
    reggi Member Posts: 494
    edited February 2023


    I will wait until summer if I can to replace the lines. This radiator and almost all are not valved off so if this leaks I am screwed.





    If you can't isolate this radiator and cap that line I would say you Can't wait to change that line as failure....is going to be catastrophic.... and you can prevent it now..my 2¢

    One way to get familiar something you know nothing about is to ask a really smart person a really stupid question
    Mad Dog_2
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,228
    Hi, When you do get that apart it will be interesting to scrape it with a knife, as it looks sort of like a wiped lead joint. Do you have any other forms of heating you could use if this lets go?

    Yours, Larry
    Mad Dog_2
  • reggi
    reggi Member Posts: 494
    Summer, 🌊.. no way, .. do a temporary repair if you can't do the project...g/l


    One way to get familiar something you know nothing about is to ask a really smart person a really stupid question
    Mad Dog_2
  • Jamie Hall
    Jamie Hall Member Posts: 22,878
    Could be wiped -- hadn't thought of that, @EBEBRATT-Ed . In which case... even more urgent to get it fixed, as the lead may have crystallized and could let go quite unpredictably. Above all, figure out a way to put no stress on that bit of pipe at all, if it can be helped. Come apart in your hands.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Mad Dog_2
  • eclecticmn
    eclecticmn Member Posts: 121
    If it goes I will have to clean up the water mess, shut off the system, drain the system, and at the least cap off that tee. What would the best emergency fix be? Two part epoxy forced into the cracks? What kind of two part solution? There is high heat and also metal fiber reinforced I think.
    I am not going to apply any force to anything near that pipe. I will put a garbage can in the room under that pipe to catch any water.

    The previous owner liked to cover stuff up. But for the sheet rock ceiling below I would have found this earlier but I should have inspected it earlier. Then again no other radiator has this problem. The second floor bathroom is above the first floor bathroom. So he sheet rocked the first floor bath ceiling. The first water incident lead to black mold and I tore the ceiling out.
    Home owner near Minneapolis with cast iron radiators, one non working slant fin now ripped out, and hot water heat.
    Mad Dog_2
  • reggi
    reggi Member Posts: 494
    Eureka!   Of course.. take a closer look at the ridges on the shell...
    Someone ALREADY epoxied this ( quite well by the look of flats) ..
    Those are fingerprints impregnated when it was applied..
    Who knows what is under the shell as it's obviously failed...the fitting may not be as bad as repair looks now...
    Think of it as being encapsulated.. and that's the outer cover..
    Now I wouldn't bet the house on it ... 
    But your epoxy/ garbage can idea isn't much of a plan anyway..
    It does need to be repaired correctly.. for now though???
    One way to get familiar something you know nothing about is to ask a really smart person a really stupid question
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,692
    Dude.. listen to the pros..fix that NOW!! What are you waiting for?  Thousands in water damage?  Maybe even personal injury?  Its plumbing man...Get a surgeon in and cut that Cancer ♋ out!  Before it metastasizes...I have found that solder joints that were never properly cleaned of flux at time of installation slowly destroy the joint like a slow and steady plague...(first it goes Green...then it gets that white effervescent crust...this is starts to be wet all the time....worse and worse...much like Rust with Iron Pipe.   What did Neil Young say??  "Rust never sleeps!"  Mad Dog 
    reggi
  • reggi
    reggi Member Posts: 494
    I wouldn't trust it... it looks ready to go right now

    One way to get familiar something you know nothing about is to ask a really smart person a really stupid question
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,692
    What are we waiting for?  Get in the ring and knock it out like Big George Foreman!    I'm getting antsy....Where is this job?  I'm grabbing my tools and turbotorch.....Ha ha
    I'm kinda serious....Mad Dog
    GGrosseclecticmn
  • eclecticmn
    eclecticmn Member Posts: 121
    Thanks for all the usual good advice. It might be epoxied already? Geez.
    This has been in place for at least 12 years. I will bet it lasts another 3 months until warm weather. If it cuts lose it will leak through the pipe hole and into a semi finished basement den with no ceiling, cheap paneling, and a stick on tile floor that is coming off. I will put a garbage can under the hole. I will order some 1 1/4 nipples, elbows, and ball valves to valve it off either after an emergency or during summer. I will replace the copper pipes as well.

    I decided not to apply any epoxy now for fear it might dissolve some crud blocking the leak right now.
    Home owner near Minneapolis with cast iron radiators, one non working slant fin now ripped out, and hot water heat.
  • hot_rod
    hot_rod Member Posts: 21,799
    make sure any autofill valve is turned off or the basement could become a swimming pool:)
    A low water cutoff would be wise also to prevent dry firing if the boiler is above that leak level.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • reggi
    reggi Member Posts: 494
    @eclecticmn ... Unfortunately the only certainly is nobody knows what
    "Alien " 👽 is going to emerge and how soon it's going to be stirring now that it's shell is breaking away and awaking it's sleep ... G/l





    One way to get familiar something you know nothing about is to ask a really smart person a really stupid question
  • archibald tuttle
    archibald tuttle Member Posts: 1,073
    you should be able to get someone to press valves onto the feed (is the feed also 1/2" copper?) and return for that radiator and isolate it, repressurize the rest of the system for not much more than the cost of the service call itself, especially if you share the info with them ahead of time so they are prepared and then you could have a summer leisure fix. (I'm assuming this is teed off a larger header and not circulating through other radiators in series. although stranger things have happened. if its in series with other heating loads you would need to pipe a bypass. because of the picture below the floor, i assume there is access.)
  • eclecticmn
    eclecticmn Member Posts: 121
    At some future time I will post a marked up photo of the boiler piping with questions about an air eliminator, dirtmag, low water cutoff, and automatic feed.
    For now, what is a low water cutoff and I assume it mounts on external boiler piping? I do not think I have one and have no automatic feed either. My copper boiler piping is only 11 years old but is kinda green.
    Home owner near Minneapolis with cast iron radiators, one non working slant fin now ripped out, and hot water heat.
  • mattmia2
    mattmia2 Member Posts: 9,392
    I think your leak is at the threads, you can see a little trail of corrosion at the upper left. Looks like someone misdiagnosed it and globed some epoxy putty or some other type of putty around it. I don't think the mass of putty and carpet fibers is sealing anything but just a poor repair attempt of the wrong problem.
  • reggi
    reggi Member Posts: 494
    mattmia2 said:
    I think your leak is at the threads, you can see a little trail of corrosion at the upper left. Looks like someone misdiagnosed it and globed some epoxy putty or some other type of putty around it. I don't think the mass of putty and carpet fibers is sealing anything but just a poor repair attempt of the wrong problem.
    So it would be the same as this... just puttied up over a decade ago for a "drip" .. perhaps? 
    Hmmm 🤔... I concur.. they didn't cover it for no reason..👍 What has it turned into 10 years later . ..... we'll have to wait to see 
    One way to get familiar something you know nothing about is to ask a really smart person a really stupid question