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Can copper pipes be installed with a steam boiler?

Here are several reasons for NOT using copper on steam.....right out of the Burnham Installation Manual. Hope this helps.

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.


  • Cindy_2Cindy_2 Member Posts: 2
    Steam boilers and copper pipes

    Can copper pipes we installed with a residential steam boiler? If not why not?
  • Big EdBig Ed Member Posts: 1,117
    Depends Where

    Copper should not be use on the near boiler supply piping for the solder joints break on a proper header set up...Too tight on proper header set up...

    It can be used on a return if dieielectric coulping are used where it joins the iron pipe...
  • Steamhead (in transit)Steamhead (in transit) Member Posts: 6,688
    Not on the steam header

    or any other pipe that carries steam, for the reason Big Ed mentions. I would not use copper on dry (overhead) returns either since it is possible for steam to get in them.

    But on a wet return (below boiler water level) copper is fine, since these pipes are filled with water. Steam cannot enter a wet return.

    If you are dealing with a contractor who wants to use copper on steam pipes, tell him he either uses threaded black steel or you will find another contractor. If he won't budge, go to the Find a Professional page of this site to locate someone who will do the job right. BTW, many contractors who cut corners by using copper on steam also completely ignore the manufacturer's piping instructions too. This is sure to cause problems.


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  • STEVE PAUL_3STEVE PAUL_3 Member Posts: 126
    Copper on steam

    A few years back, I would have totally agreed with you and not use copper on any steam piping. Now with the introduction of Propress I won't hesitate to use "L" copper all throughout the system, on the steam or return piping. With the proper "O" rings Propress copper might even be a better choice than steel. It will be more forgiving with expansion and contraction. Like any product, it must be installed to the manufacturers specs. There is always a tendency for us to shun something new as being a "SHOEMAKERS" job.
    We have many Propress steam jobs out there and have not had any failures or leaks.
  • clammyclammy Member Posts: 2,513
    with steam head

    How long ? peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • David_5David_5 Member Posts: 250

    I've seen systems piped with copper that were 20 years old. They showed no signs of trouble. The idea is frowned upon at this site.

  • Tim GardnerTim Gardner Member Posts: 183
    i don't know about copper

    but the black steel the dead men put into my house in 1925 has certainly lasted. I cut into my header in two places recently to add radiators and the big black pipe looked as good as new.
  • Ron SchroederRon Schroeder Member Posts: 998
    Can You??

    Yes you can, but should you?? I am with Steamhead and Big Ed on this one.
  • gerry gillgerry gill Member Posts: 2,987
    i'm with ed & steamhead..

    my theroy is that if the dead men wanted copper in a steam system THEY would have done so..but they didn't..thats good enough for me.

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  • Keith_8Keith_8 Member Posts: 399
    why bother?

    If steel pipe has stood the test of time, why bother using copper? Is the material less expensive? No, not really. in the scheme of things how much labor are you really going to save? 20% maybe? On a boiler replacement that doesn't amount to enough savings to take the gamble.

    I can personally atest to a commercial application where my company substituted copper for the boiler room condensate piping, where schedule 40 steel was specified in a commercial application, without the enginneers written consent. 5 years later it is all getting ripped out because of severe corrosion issues reported thru out the system.
    In my opinion the copper did not cuase the problem, it was a poorly maintained water treatment program. It was the reaction of the chemically induced water to the copper that caused the problem. How ever if the copper was not present in the system we wouldn't be dealing with this mess now.

    Needless to say, I agree with the other posters who say if it was good enough for the dead men then it's good enough for me. Maybe thats old school thinking but it has stood the test of time. Some things just are what they are and should stay that way.

  • Cindy_2Cindy_2 Member Posts: 2
    Copper pirpes installed wiht residential steam boiler

    Thank you all for your advice about the use of copper pipes.
    The reason I have asked is because I have a boiler that is cracked. I have had 5-6 companies out who all have given me differnt opinions about thsi subject. I need to insatll a new boiler but the pipes that are already there are copper. So the question really is should I pay almost double to have the copper replaced or should I leave them and see if they cause a porblems down the road. The current pipes have been there for 18 years.

  • Boilerpro_3Boilerpro_3 Member Posts: 1,231
    Also, I wonder about life......

    What king of strength do you have in copper when there are problems like water hammer and I wonder how long the o rings will last at 215F temperature with constant movement.

  • Steamhead (in transit)Steamhead (in transit) Member Posts: 6,688
    You were lucky these 18 years

    but I wouldn't push your luck any further. Replace them with black steel.

    Any idea what caused your boiler to crack?

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  • David_5David_5 Member Posts: 250
    Why bother

    Well 20% seems like a pretty high number to me. Copper has also stood the test of time. In the system you mention many people would be ok using copper for the condensate piping. It failed because of poorly maintained water treatment in your opinion. I doubt steel would hold up any better to poorly maintained water treatment.
    I respect the dead men and thier achievements. If I find a better way to do sometning than I will do it, just like the did.

  • David Sutton_6David Sutton_6 Member Posts: 1,072
    Steamhead got my vote!!

    Copper has its place but not on suply piping, i use it under the water line only....David

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  • STEVE PAUL_3STEVE PAUL_3 Member Posts: 126
    How Long

    Fair and reasonable question Steamhead. We have been using copper with ProPress about 3 years. Granted this is not a long term field test. But so far no problems.
  • JohnNYJohnNY Member Posts: 2,471
    Steamhead and others...

    I had a client with unusually high water consumption in his steam boiler. He had a copper header and no leaks anywhere. We were figuring to change the boiler when we decided we'd start by installing a proper steel header for the heck of it (Oh, and $1,800). As soon as the copper was gone, the make up water turned to normal usage.

    I guess the point is that steam, being a gas, escapes through very tiny openings in copper joints. We have a preconceived idea of what a leak in copper pipe looks like but that's not always the case. The opening in the joint may not look like a leak at all and still pass vapor.

    Anyway, that's been my experience.

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    For troubleshooting and private consulting services, find John "JohnNY" Cataneo here at :
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    Or email John at [email protected]
    John is the Boilers and Hydronic Heating Systems Course Instructor at NYC's Mechanics Institute, a professional Master Plumber, licensed by The Department of Buildings of The City of New York, and works extensively in NYC while consulting for clients in and out of state.
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  • Long Beach EdLong Beach Ed Member Posts: 700
    Another opinion...

    ...which is the same as the rest. Copper has no place carrying steam. It will only cost you more to replace down the road. It's probably piped wrong anyway.

    Ditch the plumbers who want to save the copper it or install it new. They are the one's who probably woun't pipe the boiler correctly also.

    Long Beach Ed
  • Tom Anderson_2Tom Anderson_2 Member Posts: 9

    Copper does not like an acidic environment. Steam condensate is often acidic.

    Not once have I ever come across for steam or cond piping in any commercial or institutional building in over 25 years. Never seen it specified either.

    Has copper stood the test of time? Real time, like 25 years plus?

    Tom Anderson
  • gerry gillgerry gill Member Posts: 2,987
    out of curiosity, does

    the manufacturer authorize its use for steam?

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  • Jim PompettiJim Pompetti Member Posts: 552
    I guess

    If you felt so strongly about using copper headers ,you would not have a problem with a warranty 20 or 30 years. In a business were anything can happen, I feel better doing the job once and doing it right.We make a living repairing other people mistakes.Jamie posted some picture today of his re-piping jobs {before only}.These contractor walked away from these jobs took the money and refused to return. I've heard contractors say "I didn't bid it that way", A job done wrong reflects poorly on all professionals, hell, doctor carry malpractice insurance and pay dearly for their mistakes. In our business the customer, pays for our mistakes by either poor results and costly repipes.I hope my ramblings make so sense.
  • STEVE PAUL_3STEVE PAUL_3 Member Posts: 126

    Yes, ProPress does supply "O" rings for steam
  • Erich_2Erich_2 Member Posts: 3

    Read somewhere that welded headers can split boiler sections because of expansion issues.. . the steel can expand more than the cast iron block and rips it right apart. I don't see why the same exact thing doesn't happen with copper. The copper header that you have now, if it has only a few fittings put in the wrong spot, might have cracked or split your boiler. Just a thought.
  • Big EdBig Ed Member Posts: 1,117
    Double ?

    I could not see where it would cost double piping in iron unless your installer does not own a diestock(tool to thread pipe) ? "Gee Lady , if you want iron your paying for the tools"
  • Steamhead (in transit)Steamhead (in transit) Member Posts: 6,688
    Better yet

    on smaller boilers, you usually don't need to thread anything- just use pre-cut nipples and maybe a coupling or union here and there.

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  • Boilerpro_3Boilerpro_3 Member Posts: 1,231
    I have seen that!

    Looked at a 4 year old LGB with two risers in a welded header and the gaskets were already starting to leak. The boiler had been short cycling for awhile due to the installation of too small of a transformer, so that only accelerated the problem.

  • Tony Conner_2Tony Conner_2 Member Posts: 443
    I Doubt...

    ... that the welded header had anything to do with the boiler problem - unless the guys that put the header in didn't know how to properly fit pipe, and did something dopey like use jacks or come-alongs to pull things into alignment. (I have witnessed such piping attrocities...)

    The coefficients of expansion for cast iron and carbon steel are virtually identical, and given the relatively low temps involved, and the short distances (the length of a boiler), welded headers should be of no consequence at all.
  • Big EdBig Ed Member Posts: 1,117

    They can also send the gofor to Homedepot in a fix.... " Give the guy in the plumbing isle these dimentions and on the way back a large light and sweet , hurry "
  • Eddie MEddie M Member Posts: 26

    I just had my utica boiler replaced with a WM. The piping above the boiler was all copper. I was adding water 2x a day which created a hole above the water level. Plumber showed me all the little holes between the copper connections which steam possibly leaked and created that hole in time. I now have all steel pipes and i barelly use up to an inch of water on the site glass a month.
  • Paul PolletsPaul Pollets Member Posts: 3,303

    as a Fitter, I'm aghast at those that would consider copper on steam. A properly designed steam header may use swing joints to absorb the expansion, if required. If the header isn't stressed, it won't crack the boiler tapping.

    I've seen many a copper header in the NW, where steam is not so common. Inevitably, the copper must be replaced with iron. I'd be interested to know if Ridgid will warrant their ProPress fittings for steam. BTW, a large 3" copper ProPress Tee cost 4x as much as a threaded steam tee. The labor savings may be large, but I'd be very surprised if it passes the test of time.

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  • But ......

    as far as I know , not one boiler manufacturer will void a warantee if copper is used on a steam boiler's piping .

    I am definitely not an advocate of using copper on steam mains , but we do see more and more copper used when cast or steel needs to be replaced .

    I'm not exactly proud of this job , but 2 of the 3 mains were copper already , and I have no doubt the pipe and solder will hold up for decades . And we were able to give the family heat in one cold day .
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