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radiator snaps after heat being off

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I have a big old steam radiator that will emit a loud Snap or pop after it has cooled. Really starting at times. Not sure where on the radiator it is coming from . Any ideas how to find it, .....it often it takes quite a while until it does this. I'm thinking it may be the top joints?,..first thought was to spray all joints with Trflow, a teflon based lubricant but thought that might not smell too good when the heat came on,..Wish it would stop...

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  • Canucker
    Canucker Member Posts: 722
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    My hot water rads pop when they cool off but it's the feet making the noise against the floor. I'm too lazy to put pieces of milk jug under them to stop it right now
    You can have it good, fast or cheap. Pick two
  • Rick_41
    Rick_41 Member Posts: 67
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    Hummm I don't THINK its the feet,..it sounds sharp like someone hitting it with a hammer, NOT like water hammer and it happens when the heat has been off and the radiator is cool,
  • acwagner
    acwagner Member Posts: 505
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    It's likely the supply pipe rubbing up against the floor or joist and releasing when it cools and contracts. Check the opening where the pipe comes through the floor and see if it rubbing.

    Also, is the radiator solid on its feet or does it wobbly some? If it wobbles, try putting some shims or pennies under to stabilize it.
    Burnham IN5PVNI Boiler, Single Pipe with 290 EDR
    18 Ounce per Square Inch Gauge
    Time Delay Relay in Series with Thermostat
    Operating Pressure 0.3-0.5 Ounce per Square Inch

  • ethicalpaul
    ethicalpaul Member Posts: 5,729
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    One of mine makes expansion sounds during heat up that might be the same as you are hearing. It is the sections or joints within the radiator itself, definitely not the supply. It’s a very distinct TINK like the sound a stuck bolt makes when it finally goes free

    I have seen suggestions to carefully try tightening up the tie rods if you have them. Just a little bit then see how it goes. You don’t want to break a bolt.
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • Jamie Hall
    Jamie Hall Member Posts: 23,428
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    If you do decide to try tweaking a tie rod... as @ethicalpaul says, go easy. Those things break very easily. A couple of tips: first, make sure that when you try to turn the nut on the rod that the nut is turning on the thread. If the nut is frozen (quite likely -- paint, rust, whatever) you can fool yourself into thinking that the nut is turning, but instead you are twisting the rod itself. This will break the rod. As part of this, back the nut off first -- loosen the rod. Then, when you do go to tighten it, do it with the radiator hot, and get the nut just beyond finger tight. Don't go all gorilla on it. That will break the rod too.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    ethicalpaul
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
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    If you do break one, they're easy to replace. Just buy some steel rod and thread each end, or, if you don't have any dies, and don't care how it looks, use a piece of threaded rod.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Canucker
    Canucker Member Posts: 722
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    > @Rick_41 said:
    > Hummm I don't THINK its the feet,..it sounds sharp like someone hitting it with a hammer, NOT like water hammer and it happens when the heat has been off and the radiator is cool,

    What you describe is what I hear from mine periodically and they can be cooled off for some time before it happens. Try something under the legs that slide easily. If the noise goes away, you know what it was. If it doesn't, then the troubleshooting continues
    You can have it good, fast or cheap. Pick two