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Need advice for what to do with old, crusty, leaking radiator valve.

jtor1134
jtor1134 Member Posts: 27
edited September 2018 in Strictly Steam


When I bought this house last year I discovered that one of the radiator valves has been leaking, seemingly around the union nut. I schmeared some RTV sealant around it, which slowed the leak somewhat, but I just dealt with it for the rest of the winter by keeping a small bowl underneath. Now I'd like to fix this properly. Also this valve wont close all the way, or at least when closed all the way, steam still gets through. I'm thinking that changing this valve is probably the best course of action at this point.

I think this is what I need: https://www.supplyhouse.com/Bluefin-RVST150-1-1-2-FIP-x-Male-Union-Steam-Angle-Radiator-Valve?gclid=Cj0KCQjwlqLdBRCKARIsAPxTGaXbPROy39Tq4FljvSz_9-YAkbt3H_kneOIirz8eU35x42IBQpwd7NoaAnKiEALw_wcB#reviews-content

However I'm concerned about the height of the valve. Based on the pictures alone it seems the new valve is shorter, and I'm concerned there'll be a height mismatch once the new valve is screwed onto the riser.

Also this will be the first time changing one of these valves as I'm new to steam heat, but I've been an auto mechanic for most of my life and at least know which end of the wrench to hold.

Any suggestions? Thank you in advance.

Comments

  • luketheplumber
    luketheplumber Member Posts: 134
    I that looks bad I would replace it
    I just earned my GED and am looking for a apprenticeship with one of these steam gurus on this site!
  • luketheplumber
    luketheplumber Member Posts: 134
    but you can get a little play with the pipe and get a pot belly valve they tend to last longer
    I just earned my GED and am looking for a apprenticeship with one of these steam gurus on this site!
  • Jamie Hall
    Jamie Hall Member Posts: 17,060
    It does look as though it has been leaking around the union. The first thing to do is to take the union apart and thoroughly clean the mating surfaces and look and see if they are nice and smooth with no scratches or the like. Then try to put it back together. Remember with plumbing unions that the seal is on the mating surface -- not on the thread -- and that they aren't intended to compensate for any significant misalignment. You may find when you take it apart that the feed pipe drops; no problem, so long as you can pull it up again. Make sure that the thing is lined up, and then tighten the union. Do NOT overtighten -- that can crack the nut. You may find that rocking the radiator slightly while tightening helps to get it snug.

    Now. Hopefully that fixes the leak at the union.

    I can't really tell from the photo, but it doesn't look as though the valve is leaking at the bonnet or the stem, which is good. However, if it really lets a significant amount of steam through, you may want to take the valve apart and check the valve seat. They get tired, but are usually replaceable. If you do, you will need to replace the packing around the stem. Again, when you put it back together the bonnet needs to be snug, but don't reef on it -- only enough so it doesn't leak. They crack really easily.

    Now... hopefully you are all set. However...

    If you still need to replace the whole valve, you have picked a good enough valve. However, note that it comes with the spud. The spud and the valve are matched. You will have to get the old spud out of the radiator, and that can be a real bear. But you do have to do it; don't even try to replace just the valve.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Steamhead
    Steamhead Member Posts: 14,838
    Are you sure the existing valve is 1-1/2" like the one you linked to?
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • jtor1134
    jtor1134 Member Posts: 27

    It does look as though it has been leaking around the union. The first thing to do is to take the union apart and thoroughly clean the mating surfaces and look and see if they are nice and smooth with no scratches or the like. Then try to put it back together. Remember with plumbing unions that the seal is on the mating surface -- not on the thread -- and that they aren't intended to compensate for any significant misalignment. You may find when you take it apart that the feed pipe drops; no problem, so long as you can pull it up again. Make sure that the thing is lined up, and then tighten the union. Do NOT overtighten -- that can crack the nut. You may find that rocking the radiator slightly while tightening helps to get it snug.

    Now. Hopefully that fixes the leak at the union.

    I can't really tell from the photo, but it doesn't look as though the valve is leaking at the bonnet or the stem, which is good. However, if it really lets a significant amount of steam through, you may want to take the valve apart and check the valve seat. They get tired, but are usually replaceable. If you do, you will need to replace the packing around the stem. Again, when you put it back together the bonnet needs to be snug, but don't reef on it -- only enough so it doesn't leak. They crack really easily.

    Now... hopefully you are all set. However...

    If you still need to replace the whole valve, you have picked a good enough valve. However, note that it comes with the spud. The spud and the valve are matched. You will have to get the old spud out of the radiator, and that can be a real bear. But you do have to do it; don't even try to replace just the valve.

    Thanks for the info. I do know about having to change the spud, and yes it looks like a pain, but I think with careful use of a hacksaw blade and chisel I can manage. I'm more worried about ending up with a height mismatch or worse, damaging the riser pipe.
    Steamhead said:

    Are you sure the existing valve is 1-1/2" like the one you linked to?

    I think so? I held up a ruler to union and eyed it real good. Seems like 1-1/2" to me but maybe I'm looking at it the wrong way?
  • JUGHNE
    JUGHNE Member Posts: 8,943
    Sized are determined by inside diameter.
    You can measure the outside circumference with a tailor's cloth tape.
    Post that here and someone can tell you the ID.
  • Phil53
    Phil53 Member Posts: 70
    I believe Marsh makes valves that are longer and may better match what you have.
  • Jamie Hall
    Jamie Hall Member Posts: 17,060
    If you do decide to change the valve rather than repair it, be aware that you are in for an interesting day. Be careful taking the spud out not to damage the threads in the radiator -- that will scrap the radiator. And be careful in taking the valve off the riser not to twist the riser even slightly. That will cause a hidden leak. It's not fun.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • jtor1134
    jtor1134 Member Posts: 27
    I'm starting to think I should call a plumber lol.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,276
    @jtor1134

    you can do this. I have done a lot of this. Get and angle grinder with some cutting disks.
    1. Take a couple of hammers and put one on the back of the union and hold it tight to the union as a back up. Rap the opposite side of the union. You don't have to smash it, just 3-4 good raps. The union should then come loose with some pipe wrenches
    2. Move the rad out of the way so you can work on the riser. Measure up from the bottom of the old valve 1", make a mark and take the grinder and cut the old valve off at the mark horizontally. You won't hit the pipe as the old pipe makes in no more than 3/4"
    3. Once you cut the valve out make a few vertical cuts in the remaining part of the valve around the circumfrence Don't make the cuts too deep go down to the threads and leave the last 1/8"
    4. You can then wrench off the piece or cut it with a chisel as it will be weakened by the cuts.
    5. A hacksaw or sawzall used with care can cut the old nipple out of the radiator also with a hammer and chisle
    6. Now you got the hard part done.
    7. As long as the new valve is reasonably close you can make it fit
    8.
    Worse case if the new valve is shorter and you can't pull the pipe up put an "extension coupling" ( male x female coupling) on the riser...then the new valve. Then shim under the radiator legs if need be
  • Your best bet is to fix the old valve. Clean up the mating faces of the Union, as Jaimie advised, and inspect the bonnet, and packing nut while the system is running. If the packing nut shows any sign of leaking, then repack.
    Save your money for some good main venting, and a low pressure, (0-3 psi) gauge!—NBC
  • jtor1134
    jtor1134 Member Posts: 27
    Got the radiator off. The union nut was surprisingly easy to remove. The mating faces of the union don't seem too bad. No gouges or corroded spots. I'm going to try and clean them up with steel wool and use RTV sealant and put it back together and see what happens.


  • Jamie Hall
    Jamie Hall Member Posts: 17,060
    Keep the sealant to a minimum -- only a very thin layer!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Use dishwashing liquid on the faces of the union, and rock it from side to side as you tighten it. Don't put sealant on it.--NBC
  • jtor1134
    jtor1134 Member Posts: 27
    Success! There’s a plumbing supply store near my house so I went to pick up some steel wool and I asked an old-timer there what I should use as a sealant. He handed me a jar of “real tuff” and told me how to use it. So I polished up the mating surfaces with the steel wool, applied a thin layer of the stuff, nearly threw out my back trying to get everything back together and cranked the union nut good and tight. Ran the boiler and it’s no longer leaking. Of course now it’s leaking from the valve stem but I know how to repack a valve so I’m not worried. I’m just glad I don’t need to change that valve right now. Wasn’t looking forward to that.
    JUGHNE
  • luketheplumber
    luketheplumber Member Posts: 134
    just saying i would took the opportunity to patch the floor while the rad was off
    I just earned my GED and am looking for a apprenticeship with one of these steam gurus on this site!
  • jtor1134
    jtor1134 Member Posts: 27
    It's actually normally covered by a radiator cover, so you don't see it. I plan on replacing the flooring in the future so I'm not going to bother until then.