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Using Brass Unions

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luna12
luna12 Member Posts: 14
edited August 1 in THE MAIN WALL

I'm installing a Weil-McLain CGa-6 cast iron boiler. The piping system is a monoflo from the 1950s. I will be using black pipe for the near-boiler piping. A certain area of my setup is close quarters, and I want to use a male by male union. I wasn't able to track down a 1-1/4" one made from black malleable iron, so I got the only one I could find and it's made from brass. However instead of being a ground joint union, metal to metal, it has a washer that I think is teflon. The union is rated at 250 degrees. Here's the link: https://www.amazon.com/dp/B0GCCYBMLH?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

Can I still use this in my piping system? When I saw that it had a washer, I thought it seemed kind of iffy.

PXL_20260801_225016883.MP.jpg PXL_20260801_225043529.jpg PXL_20260801_225141728.jpg
Robert_H

Comments

  • mattmia2
    mattmia2 Member Posts: 17,760

    kinda weird but should be fine, teflon is fine at hydronic heating temps.

    luna12
  • Jamie Hall
    Jamie Hall Member Posts: 27,646

    I can't think of a good reason why it shouldn't be fine. I suspect, though, that even more than the ground joint type you will have to observe the usual cautions — as close to perfect alignment, both linear and angular, as you can manage, and go easy with the wrench. Be a gorilla and the washer will fail.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    luna12
  • Big Ed_4
    Big Ed_4 Member Posts: 3,558

    From the photo it seems like the left side set of threads are straight BPS and the right side are tapered NPT ?

    There was an error rendering this rich post.

    luna12
  • mattmia2
    mattmia2 Member Posts: 17,760

    i don't know if we said this in your other threads but make sure you put enough pump on the monoflo to make the water take the run and the branch. the flow you need will probably be more than btu/hr = 500 * 20 f degrees * gpm will give you.

    luna12
  • luna12
    luna12 Member Posts: 14
    https://forum.heatinghelp.com/discussion/comment/1901263#Comment_1901263

    Both sides are NPT. The pic is a bit misleading.

  • luna12
    luna12 Member Posts: 14

    I plan to use a Grundfos UPS26-99FC

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,716

    Why not use a black union and two close nipples?

    IMHO your always better to use standard run of the mill fitting you can get anywhere in a pinch.

    Male x female unions, street elbows I try to avoid all the weird stuff.

    In the first place it usually costs double or more than the equal normal fittings

    And when it leaks you can't find another on except on Amazon. There are not many cases where you "have" to use weird fittings with a little planning.

    Where is that union made China or Tiwan?

  • luna12
    luna12 Member Posts: 14

    The close nipple and regular female unions added more space and the close nipples are kind of hard for me to use. But at this point I may need to resort to that.

  • mattmia2
    mattmia2 Member Posts: 17,760

    it is easy enough to install close nipples by turning the fittings that they screw in to. get an inside pipe wrench if you want to remove them without damaging them although you really shouldn't have to.

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