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Remove valve stem assembly between heating cycles?

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Hey all, I’ve learned so much about the steam system in my NYC coop from reading this form. I successfully replaced the radiator in my apartment before this year’s heating season and it’s working great!

Unfortunately, I wasn’t able to replace the ancient supply valve because of how closely it’s positioned to the wall. A week or so ago, I noticed that steam was leaking from where the handle assembly screws into the valve (see attached photo). It turns out that the nut there was loose. I tightened it down and that solved 90% of the leak, but there’s still a small amount of steam leaking from one area (see photo) and creating small water droplets. The water isn’t enough to be concerned about, but the constant sound of the steam releasing is driving me crazy (and I'm sure not great for the system as a whole).

What I’d like to try is loosening that nut again so that I can remove the entire stem assembly, replace the corroded rubber gasket inside (I have the new part from a new valve), and then apply some pipe dope to the threads before tightening it back down, hoping that’ll resolve the last little steam leak. I’m also thinking I may as well replace the packing nut with a new one as well. It's not leaking, but there's no resistance when I turn the supply handle.

Two questions:

1. Does this sound like a solid plan?
2. Assuming I move quickly, can I safely do this repair between heating cycles, rather than asking the coop to shut off the entire boiler (which is unlikely to ever happen)? If so, is there a minimum amount of time I should wait after the cycle shuts off before removing the stem assembly?

Thanks so much for any help!



Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
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    That was not a good idea, taking that valve apart at the joint. Sometimes there is a small gasket in there. My best advice is to loosen it a bit (one or two turns) and try to work some teflon tape thread sealer in that seam and then try to re-tighten it. Be very careful... live steam will pour out of that valve if you let is come completely apart.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • sofimarshall
    sofimarshall Member Posts: 5
    edited November 2021
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    Thanks, Ed! Trying to push in some teflon tape is a good idea. And just to be clear, I didn't take the valve apart there, it's very old and I simply discovered that it was loose. Live steam won't pour out if I work between heating cycles, correct? I would never attempt to mess with it while steam is actively coming into the radiator.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,544
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    @sofimarshall

    Even a professional wouldn't try to repair between cycles
    pecmsgHap_HazzardEdTheHeaterManNYtimebomb
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
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    I guarantee you something will go wrong, and the next cycle will start sooner than you think it will.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
    EBEBRATT-Ed
  • pecmsg
    pecmsg Member Posts: 4,861
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    Thanks, Ed! Trying to push in some teflon tape is a good idea. And just to be clear, I didn't take the valve apart there, it's very old and I simply discovered that it was loose. Live steam won't pour out if I work between heating cycles, correct? I would never attempt to mess with it while steam is actively coming into the radiator.

    W R O N G

    When working with steam Double isolation is a safety Requirement. the main valve(s) need to be closed or boiler shut down to prevent Injury!
    EdTheHeaterManNYtimebomb
  • sofimarshall
    sofimarshall Member Posts: 5
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    Thanks all, sounds like I'll tough it out this winter and do the repairs in the spring.
  • Chris_L
    Chris_L Member Posts: 336
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    If the only place it is leaking now is at the bonnet, you could try fixing it from the outside without taking it apart.

    I'd see if I could find a short piece silicone hose (or some soft rubber that can take the heat) that fits snugly over the bonnet, and use a hose clamp to tighten it down.
    sofimarshall
  • sofimarshall
    sofimarshall Member Posts: 5
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    Thanks, Chris, that's a great idea. I'll try it!
  • mattmia2
    mattmia2 Member Posts: 9,670
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    Use teflon tape or teflon string packing. Be careful with the old packing since it was frequently asbestos, sometimes coated in graphite.
    Brent H.Hap_Hazzard
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
    edited November 2021
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    In no way was i suggesting that the valve stem be removed. just loosened enough to slide some teflon in the seam. i hope the OP would not think that removing the stem between cycles was a good idea. IT IS NOT A GOOD IDEA. Teflon is just a trick i used successfully in the past.

    I like @ChrisJ's idea. Maybe a bicycle tire tube from one of those skinny tube racing bikes might fit snuggly.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
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    Only try to fix things between cycles if the time between the cycles includes the months of June, July and August. :D

    But seriously, if you're not the one controlling the boiler, even that isn't safe. You never know when somebody might fire up the boiler to test something in the middle of summer.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24