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

eclecticmn

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

SlamDunk

Intergranular corrosion between two different metals and water as an electrolite? Just a guess. Bad guess. Galvanic corrosion.

hot_rod

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.

eclecticmn

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

Jamie Hall

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.

Waher

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.

reggi

A zoom of your close up shows how close to failure this has progressed.... and the pet hair 

Long Beach Ed

Maybe the pet hair is reinforcing the crack...

hot_rod

Double glove for this repair😗 Maybe a mold respirator 

reggi

@eclecticmn

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¢

Larry Weingarten

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

reggi

Summer, 🌊.. no way, .. do a temporary repair if you can't do the project...g/l

EBEBRATT-Ed

Maybe someone put Bondo or something over it. It's real ugly

Jamie Hall

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.

eclecticmn

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.

reggi

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???

Mad Dog_2

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

I wouldn't trust it... it looks ready to go right now

Mad Dog_2

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

eclecticmn

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.

hot_rod

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.

reggi

@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

archibald tuttle

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

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.

mattmia2

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

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