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Galvanized or Black pipe for old HW system

Are you certain they're galvanized and not just painted silver? Typically black pipe is the only type of steel pipe used with hydronic systems. In my experience galvanized pipe in hydronic systems (I've only found such in repairs--not original) tend to scale terribly just like they do with potable water.

Comments

  • Phil_8
    Phil_8 Member Posts: 42
    glavaanized or black pipe for old hydronic system

    Old 1929 house had new hardwood floors installed thus existing galvanized steel risers are about 1 inch too short. Should I remove the existing risers and replace with galvanized steel pipe or can I use black pipe. If I run into problems backing out the old risers are there any easier solutions. Thanks much
  • Phil_8
    Phil_8 Member Posts: 42
    black pipe riser extensions

    Thanks Mike. Yes this existing pipe is black pipe and the system was origionally gravity fed.

    If some of the old risers don't back out easily, any tricks on extending the risers about an inch?

  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    Use black pipe!

    Until someone invents a pipe stretcher, I know of no way to extend 3/4" or larger screwed pipe by an inch.

    If the rads are fed with fairly long horizontal runouts before the riser nipples, there's a decent chance you'll find enough "wiggle room" without replacing the riser. Sometimes this will only work on one of the two pipes.

    Best way I've found to loosen old joints in hot water systems is to get some cheap silicon spray. "Petroleum distillates" will be the first listed ingredient. Spray the joints (or pipes if you can't directly access the joint) VERY generously 6 or 7 times over a couple of days. This seems to soften even the most cement-like pipe dopes used by the dead men. Be careful with hidden connections. Usually things won't move too much and you'll be able to thread in the new pipe, but if things were in a bind or you've really torqued the joint to break it, it may move. If the riser goes crooked once you've loosened the joint, but not opened it fully, you can almost bet that the fitting will move considerably. Try to use your pipe wrench as a lever to straighten the riser.
  • Phil_8
    Phil_8 Member Posts: 42
    black pipe riser extensions

    Thanks Mike,

    On the risers where we don't have direct access to the joint I'll spray the solvent on the outside of the pipe and hope some flows down into the joint.
  • scrook_2
    scrook_2 Member Posts: 610


    Kano Lab's Kroil penetrating oil or Marvel Mystery Oil may help loosen them up. Maybe.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    The cheap silicon spray (petroleum distillates the first ingredient) to loosen some joints with a cement-like pipe dope when I was doing nothing but collapsing 1" pipes with a 4' cheater bar on a 3' pipe wrench. Even worked on a coupling about 6' down inside a wall.
  • JK_3
    JK_3 Member Posts: 240
    yes they make extenders

    most plumbing supply houses(at least in my area) carry male x female couplings and depending one the size will raise oabout 1 inch. HAPPY THANKSGIVING

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