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Leaking Steam Pipe in Basement

RichSRichS Member Posts: 3
Good afternoon,

I live in northern NJ and am an IT admin. A pipe in my basement started leaking right under where the radiator is upstairs. I took some pics of the wall, pipe and the elbow joint where it appears to be hissing as well...I would guess indicating a leak.

So, should I attempt to repair something like this on my own?

Is there a way to seal off the pipe without replacing?

This pipe/radiator is also the main source of loud banging that keeps me up all night, is there a solution that I can apply that might solve both issues?

Thanks for your help in advance! I just got a new gas furnace installed last year, so the main unit shouldnt be the issue.


  • don't mention the "f"word here

    it's not a furnace, it's a boiler!

    oddly enough, the new boiler could be part of the problem, it it had been badly installed. when your heating system was first installed, there was no banging, or uneven heat.

    from your pictures, i can't tell where the pipes are leaking, but i can see that your pipes are not insulated, which they must be for proper operation. you can easily do that yourself.

    it is possible that your pressure is too high, causing a good joint to leak. this may be caused by a clogged pigtail, or faulty pressure control.

    if you get a copy of "the lost art of steam heating" at the shop here, you will be able to see which maintenance you can do, and which should be left to a knowledgeable steam pro.

    first, get a good low-pressure gauge [ 0-3 psi], and have it put with the 0-30 psi gauge, and the pressuretrol. that way you will know what your pressure is. high pressure [over 3 psi] can destroy important parts of the system. the most desirable pressure is 8 ounces max!

    next, insulate the steam supplies with fiberglass pipe insulation, or with batts [temporary fix].

    in addition, check your main venting, as the air has to be let out, before the steam can "arrive" at the radiators.--nbc
  • Jamie HallJamie Hall Member Posts: 6,693
    It is quite possible

    unhappily, that the banging (water hammer) has taken a marginal joint and made it leak. A bad hammer can take a perfectly good joint and make it leak, so...

    If there was no banging before the new boiler, and there is now, the boiler install needs to be looked at to make sure that it was done in complete accordance with the manufacturer's directions. The near boiler piping is very critical, and it is possible that you are getting "wet" steam (water carryover) which is part of the problem.

    You should also check the pitch of the pipes in question -- they must allow water to drain back to the boiler through a main or a return.

    As to whether you can fix it yourself... well, without knowing how handy you are with pipe wrenches, and if there are any handy unions, and... in other words a good bit more info., I wouldn't care to say. Sometimes one can make a temporary repair with J.B. Weld, but it will only be temporary -- and it won't work at all unless you can get rid of the banging too.

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-McClain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • RichSRichS Member Posts: 3

    There was banging prior to the new BOILER! lol.

    The change was purely to go from oil to gas and save a few $.
  • clammyclammy Member Posts: 1,996
    steam pipe leaks

    If the leaks you are experening are on the bottom 1/3 of your piping the cause may be the lack of insulation on your piping which would enable the steam in your mains to condense more then a insulated main which usually cause some hammering and banging and usually will cause more condensate to form and will cause groving on the bottom of the steam main and over time uninsulated steam mains will develope condensate groving whih intanly cause leaks at the threaded joints where the pipe wall is the thinnest.You should do yourself a favor and check your pressuretrol and set it at .05 ut in and 1 lb differental ,check your pigtail to ensure it is not clogged ,then go to a real plumbing and heating supply house and purhase at miniun of 1 inch wall thikness fiberglass pipe insulation(do not waste your money at the big box store there pipe insulation is 3/8 or 1/2 wall and does just about nothing and is a waste of money)Also while doing all this check the pitch of your mains and raditors  If the boiler was recently installed did the installer skim the boiler when he was done withthe job or did he just install it fill it up and get his check.If your thinking of leaving your mains uninsulted to heat your basement then keep in mind you will have more leaks and will be replacing those setion of the main sooner or later and hopefully those setion will be replaced with steel pipe and not copper peace and good luck clammy PS the reason i know this is that over the years i have seen alot of excatly what i am tell you about many times over and ever job that i properly insulated  had drastic improvements in steam distrubution and lower fuel usuage and no more water hammer in most cases
  • malpmalp Member Posts: 28
    edited February 2010
    water activated pipe wrap

    I used a fiberglass repair kit to fix a leak in my mains. According to the manufacturing of the repair kit, the repair is permanent and rated for high temperatures, and so far, the repair has held. That said, leaks usually occur at the threads where the pipe is the thinnest. I lucked out in that my leak was near the mid-span of the pipe where the pipe used to sag, so there were no fitting nearby to interfere with the repair. Also, the pipe seemed otherwise sound. The damage was localized to a small section at the bottom side of the pipe.

    I think this is the stuff I used:

    I bought it at a big box store.
  • RichSRichS Member Posts: 3

    Well this is all excellent information, thanks to everyone who replied.

    I am not very handy when it comes to plumbing (when it comes to PCs or things that plug in, im great), so im going to take your recommendations to my father in law hopefully this weekend and see what he finds as well.

    For now I have turned that radiator off, and the banging and leaking has stopped and the house is still nice and warm, so that gives me a good chance to diagnose. No harm in having radiators off right?

    I cant seem to find exactly where the leak is coming from in the pipe, and im assuming its that far elbow joint. I hear hissing from there and it seems the only spot since upstairs is 100% dry. AirGroup did the installation 2 summers ago and I could have them in to do a check. I have been told by them and petro who tried to address the banging that it was not fixable. Im anxious to try the insulation you suggest! Thanks again!
  • Leaking stops when valve is turned OFF

    If the leak stopped when the radiator valve was turned off it sounds like the valve is leaking - probably at the top bonnet nut. It could be leaking where the valve connectts to the radiator but that usually results in water on the floor, check that connection for moisture just to be sure. Before replacing the valve try to tighten that up a bit, you might have to replace the packing as well.

    I agree that the pitch of the radiator and the feeder pipe should be checked to make sure the condensate can drain back to the boiler.
  • banging not fixable?

    don't believe them! just because they do not know how to quiet the water-hammer, they should not declare it unfixable. your system, when first installed many years ago was most likely quieter than some computers!

    get a copy of "the lost art of steam heating" here at the shop and start becoming facinated with steam! as you learn to observe whats happening to your system, and getting advice here, you will find your self able to do much of the maintainace on it.

    the diagnostic skills you have for computer hardware problems are similar to those for steam diagnostics!--nbc
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