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Cracked bonnet nut

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Dsisson
Dsisson Member Posts: 115
in Strictly Steam

I have a large valve that has a cracked bonnet nut. The system is losing water from it. Lucky it’s in the basement so the only damage is the loss of water but I want to fix it. Can I buy a replacement nut? I can’t figure out where. Replacing the valve is out of the question-just too much pipe that would need to be done too.

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 11,982
    edited January 12

    Picture? 

    A local machine shop may be able to fabricate one for you.   Also you can cut one pipe and replace the section of pipe with threaded pipe nipples and a union or a flange after all the threaded connections/surfaces are sealed 

    Edward Young Retired

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

  • Dsisson
    Dsisson Member Posts: 115
    IMG_8264.jpeg IMG_8263.jpeg

    I assume the bonnet nuts are unobtanium? Could I remove the valve guts and cap it?

  • Mad Dog_2
    Mad Dog_2 Member Posts: 8,502

    You could cap it, but they aren't NPT American Pipe Thread. Mad Dog

    Consulting by Mad Dog & Matt Jr.
  • mattmia2
    mattmia2 Member Posts: 16,357

    id try the hose clamp and see if it will seal up until the off season when you can replace the valve. maybe add a little more packing and don't crank too hard but the only way to get that nut, especially since i think that valve it 50+ years old would be to salvage one from another valve or have a machinist make one.

    Intplm.
  • RTW
    RTW Member Posts: 285

    interesting topic, got a question: What would cause the metal valve nut to fracture in the first place? Was it user error or abuse or just a natural occurrence. Finding that out may prevent re-occurrence

    Regards

    RTW

  • mattmia2
    mattmia2 Member Posts: 16,357

    usually overtightening, they split somewhat easily if you just crank on them instead of fixing why they aren't sealing.

    RTWLarry Weingarten
  • Dsisson
    Dsisson Member Posts: 115

    I don't know why this one cracked. I don't think it was me, but it's possible that it was.

    What type of thread are they?

  • ChrisJ
    ChrisJ Member Posts: 17,266

    If it was mine and couldn't figure out what thread that is, I'd pull the valve apart and tap the inside to whatever it'll work with and plug it.

    Just another idea..

    Matt's hose clamp idea could work too.

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

    ethicalpaul
  • pedmec
    pedmec Member Posts: 1,301

    Remove the insulation and try and identify the manufacturer of the valve. Might be able to find the manufacturer who could send you a replacement, if available. i mean if its that much work to replace.

  • RTW
    RTW Member Posts: 285

    Try to get that part from this business in MA that restores Cast Iron radiators, just may have that part lying around in the shop

    Contact — making people warm... (HOME)

    Regards,

    RTW

  • RTW
    RTW Member Posts: 285

    To original poster:

    I hope you post a follow up on your final solution, it could benefit others that currently have that same bonnet nut issue; I doubt you're the only one

    Regards,

    RTW

    ethicalpaul
  • mattmia2
    mattmia2 Member Posts: 16,357

    you could try going to a good hardware store, the kind with the faucet stems and seats and other parts and see if it matches up with a packing nut for a faucet. If you can find the same id and thread you can fix the hole size with a drill or washer depending on which way you need to go. A set of pitch gauges would help here but you could also measure a couple threads on the outside of the valve with a caliper or micrometer and divide and invert.

  • MikeL_2
    MikeL_2 Member Posts: 541

    I suggest removing the nut, clean all the surfaces, clamp it & carefully solder it. Ad a ss clamp after reassembly before tightening it against new packing…

  • 4GenPlumber
    4GenPlumber Member Posts: 107

    Remove the packing material. Clean the entire area. Solder the packing nut to the bonnet and the stem. Remove the handle bc it will never work again.

    cm6230
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,827
    edited January 29

    We pull it up, cut a strip of rubber and wrap it around the nut with a stainless hose clamp. Or press an automotive-type clamp on with a Pex-ring tool. Repack the valve and gently reapply the nut. It shouldn't have to be tight at all if the packing is good.

    Of course a machine shop can make one also. Just need a guy who has the time to do the work.

  • AdmiralYoda
    AdmiralYoda Member Posts: 783
    edited January 29

    I like the hose clamp idea….but if that doesn't work maybe try a C-Clamp at the top and bottom of the nut to close the gap in the crack? You can get a small one for $2-3 at your local hardware store.

    image.png
  • hot_rod
    hot_rod Member Posts: 27,260

    Brass can fatigue over time. It depends on age, the alloy, the amount of stress on the nut, or dezinification where the zinc in the alloy degrades from certain water conditions.

    Probably a combination of these events.

    A good welder could braze over the crack if you remove and clean it up.

    It would be fairly easy to machine a nut from bar stock once you determine diameter and pitch of the thread. That would be the best permanent fix.

    The hose clamp is a simple first step.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Long Beach Ed
  • RTW
    RTW Member Posts: 285

    Seems original poster fell off the radar after possible posted solutions. Maybe not an immediate concern to fix

    Regards,

    RTW

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