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Re-pipe return lines

I want to repipe my steam return lines which go in to the Basement floor and comes out into the boiler room and ties in to the equalizer . I want to run the return lines around the perimeter of the basement and back to the boiler. What should I be aware of before I start ? Thanks


  • nicholas bonham-carter
    new return lines

    in your configuration, make sure you can flush the line out with a "t" and valve at each end [or near a floor drain] , and run the full size pipe at floor level, set up off the floor an inch or so. copper may be used as it is below the waterline, separated from the iron pipe by a brass fitting.. i am assuming that your boiler is not down in a pit, which would make the new return higher than the boiler bottom.

    it may also be convenient to run the feed water line into this new return.--nbc
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,204
    We hang them

    We use a Hilti to mount little angle irons into the poured or block wall then suspend the returns from pipe hangers every four feet.  We also insulate the returns with Armorflex foam insulation.  

    At the ends we either install a Tee with brass plug or a domestic boiler cock.  This way the returns can be flushed with a hose.   We cap the hose fittings on the cocks to keep them from being opened accidentally.

    Drips to the returns are brought down the full size of the steam main in iron, then reduced to the size of the return below the water level.  We use brass couplings to transition to copper returns.

    We use a valve in the Hartford Loop and a Tee in the mud leg with a brass plug for flushing. 
  • gerry gill
    gerry gill Member Posts: 3,078
    what should you be aware of:

    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    Funny you should ask

    I spent my summer repiping my return (had to rip out walls, etc.) and learned a few things in the process.

    First, I wanted to change my wet return to a dry return. The thought of all that pipe sitting there full of water, rusting, really bugged me. In the end I settled for a dry return with a short mud leg. The piping I was replacing drained both mains, and I basically raised the whole thing up about five feet until, about six feet before the boiler, where it drops below the water line, then runs dead level to the Hartford loop. I used 1 1/4" pipe to decrease the turbulence so the gunk can settle out here instead of in the boiler.

    The mud leg connects to the Hartford loop at a tee fitting. On the other side of the tee I have a full-port ball valve I use to purge the sediment whenever it starts to build up or I get bored. I put a water valve at the other end so I can flush it out when I drain the system in the spring.

    I now realize it was a mistake to connect both mains to a common dry return. This allows the main with the most back pressure to push air into the other main, so balancing the system becomes a lot more difficult. If you're contemplating something similar, keep the dry returns separate. Once you get below water level you can join them.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Greg_23
    Greg_23 Member Posts: 22
    galvanized pipe

    is it ok to use galvanized pipe for return lines? And is there a transition fitting I should use from black iron or copper tube?
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846

    I briefly considered using galvanized pipe, but when I saw that the first place a pipe rusts through is usually at the threaded ends, where the galvanized coating is cut away, I realized there would be no real advantage.

    To go from steel to copper, you are supposed to use a dielectric union, but good luck finding them in sizes larger than 3/4". This is probably because hardly anybody uses them. Brass seems to work pretty well with both metals.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
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