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Single Pipe Rad Valve Leaking Condensate

eclark Member Posts: 33
Hey all - trying to straighten out some issues on my  new-to-me house and I've gotten as far as replacing the radiator vents, the pigtail and the pressuretrol, which seems to have taken care of 90% of the problem.  Right now, I have no main vent (maybe it never did, or maybe it just disappeared before I got here) and no plugged fitting or bung to put one in.  Since we're already in heating season, I'm planning on doing that next summer.

With all the other changes though, I'm no longer building 28psi and the rads are getting hot fairly evenly (venting was based on the charts available from the store here).  Pressuretrol cut-in is down at 0.5 and cutout is 1.5.  The last issue I'm hoping to resolve this winter is a valve that's leaking at the nut below the packing nut (at the top of the valve body).  I tightened it up but don't want to over-tighten since it's brass.  Any suggestions to get it sealed up?  Can I remove the nut, clean the surfaces with plumber's cloth and then use a little high-temp gasket sealant?  Should I use the anaerobic stuff?


  • BobC
    BobC Member Posts: 5,473
    It's worth a shot

    If you can get that to turn some sealant might just work, it looks like a bit of that broke off at some point. I would clean both surfaces and then treat them with some sort of degreaser to make sure there isn't any oil on the surfaces.

    I just picked up a tube of Permatex Ultra Black RTV silicone gasket maker to use on one union on my system that has a tiny steam leak. That radiator pipe has been capped off for almost a decade now but I'm going to start using that room again and it would be nice to have heat in there.

    i bought this from Amazon but it might well be available at a good automotive supply. You could try something like a JB Weld but then you would be stuck with something that could never be taken apart, the RTV will leave you with the option to try something else if it doesn't work.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Permeatex on a bonnet

    Hopefully that will work on the flat surfaces of the bonnet.

    I am less confident that it will work on the mating faces of a union, which are moving around as the system temperature changes. I would clean the ground surfaces of a union with scotch rite, and lube them with liquid soap. When tightening up the union nut, I rock the radiator slightly to cause the faces to seal.--NBC
  • eclark
    eclark Member Posts: 33
    I bet it will turn

    So I'll pull it apart and hit it with a light abrasive pad if the surfaces aren't too pitted.  Then just a bit of high temp sealant and put it back together. 

    Thank guys
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