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Suspected leak from radiator steam pipe elbow joint

jgvasa
jgvasa Member Posts: 12




A few months ago I noticed some bubbling paint on the wall next to our basement window. I cut open the wall and there is an elbow for our single pipe steam radiators that has some discoloration - I'm assuming it's this. Nothing was noticeably wet, but all of the paint on the wall was coming off extremely easily, and I was able to pull the drywall away fairly easily, so it doesn't seem to be a significant leak. Just enough to bubble the paint. This pipe is fully exposed in our living room above this point, so I'm confident there is no leak above this point.

The area of discoloration and rust on the bottom of the elbow is somewhat soft, but not significantly. These pipes are about 110 years old.

Assuming this isn't significant enough to warrant replacement, is there any type of product I can wrap or spray on this to stop any further deterioration and moisture from escaping?

Comments

  • pecmsg
    pecmsg Member Posts: 4,776
    The rotted floor boards tell me the leak is possibly from above. How's the fittings and floor near that radiator.
    EdTheHeaterMan
  • jgvasa
    jgvasa Member Posts: 12
    edited February 2023
    @pecmsg no issues above. This pipe goes up through our living room (exposed) and into a radiator on the second floor. No leaks there - that staining is likely an old issue. Prior homeowner painted the underside of the subfloor black, so you may be seeing some discoloration because of that as well . 
  • Jamie Hall
    Jamie Hall Member Posts: 23,170
    If you think it's leaking... which is quite possible... try this stuff: https://www.amazon.com/Rescue-Tape-RT01019-BRK-RT1000201201USCO/dp/B00AEBKYPG/ref=sr_1_9?crid=22UVV3AEQ29Q7&keywords=self+sealing+tape&qid=1676843777&sprefix=self+sealing+,aps,116&sr=8-9&th=1
    and make sure you really get it some good distance away from the fitting and stretched
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    jgvasa
  • jgvasa
    jgvasa Member Posts: 12
    @Jamie Hall thank you for the recommendation, I’ll give that a shot. I’m assuming start above the fitting/elbow and wrap down and away 6-12” past the fitting? 
  • Jamie Hall
    Jamie Hall Member Posts: 23,170
    got it. It's worked for me in a couple of places.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • jgvasa
    jgvasa Member Posts: 12
    @Jamie Hall confirmed that’s the leak (photo attached). Looks like a dime sized hole that has started to form. It’s on the backside of the elbow. Will that tape work around a curved surface like that? 
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,455
    Best bet is to replace the elbow in the spring or when you shut down the heat. Patch it for now.

    It is a simple job to crack that CI elbow remove the riser and clean up the threads on the old pipes and install a new elbow with Teflon and pipe dope.
  • jgvasa
    jgvasa Member Posts: 12
    @EBEBRATT-Ed thank you. That’s reassuring. By patch, do you mean wrap it in rescue silicon tape? The hole is on the backside. About the size of a dime and quite soft. 
  • Jamie Hall
    Jamie Hall Member Posts: 23,170
    The rescue tape will hold until you have time to actually replace the fitting. Not pretty, not elegant, but it works.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,273
    Hi, I'm a bit confused about what elbow is being discussed. In your first photo, the pipe above the elbow clearly shows water tracks coming down the pipe above the elbow, so there is a leak higher up. Is there another elbow up there?

    Yours, Larry
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,725
    Remember this is a steam pipe. As the steam leaks out, it is lighter than air and will go UP before it hits the wood floor or metal pipe and condense on that surface. If enough condensation accumulates, that can cause a drip of water to stain that pipe as water is heavier than air and gravity will cause the water to drip DOWN. The space behind the basement drywall and the floor cavity ware super humidified for years since that was a very small steam leak.

    Which reminds me of a story:
    This church in Cape May needed a new steam boiler and I got the job. Removed a Mills that was well over 70 years old. Replaced it with a Weil McLain 78. After operating for the first month, I got a no heat call one Sunday morning. When I arrived the water feeder had stopped feeding water. The display meter read 999. I reset it, water flowed, and they had heat. But 999 gallons in one month was a gallon or two more than I expected for that amount of run time.

    On Monday afternoon I returned to find where all this water was going. As it turns out there was dry return that came from the south hall wing of the system. That return was buried under sand in a very tight crawlspace. once I located the return pipe is discovered that 60% of the bottom ot that steel pipe was missing. Just rotted away. I also noticed that the floor supports and the floor boards for the office and bathrooms just above that buried pipe were all pressure treated lumber. That told me that this return pipe was leaking steam for some time.

    You see, I figures that the floor in the Pastor's office was getting a little spongy and that one of the members of the church, probably a carpenter or builder, offered to fix the problem. Once the carpet was removed, they found all this rotted wood. The bad wood was removed and replaced with new lumber. That church was over 70 years old, so if it took 70 years for that wood to rot out, then regular lumber would last 70 more years , Right?

    But it did not last that long. and in a few years the floor was rotting away again. Wow, that is odd. Well we know how to solve that problem. We will use pressure treated lumber. That stuff won't rot away any tome soon. Some time after that, this HVAC/Boiler guy happened to stumble across this leaking return pipe that was allowing the steam from that pipe to find its way thru the sand and super humidify the tiny crawlspace above it. Once the return pipe was replaced the boiler only used less than 1 gallon per month for make up water. I think that amount of make up water is acceptable.

    The rotted wood above the elbow in the first picture reminded me of the Pastor's pressure treated floor.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    bburdErin Holohan HaskellLarry Weingartenjgvasa