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Quiet radiator tip

We've corrected a number of issues with our one pipe, parallel flow system. After we were done with the fixes, a few of our radiators would "pop", or "bang" with each cycle. It wasn't water hammer because they would do this about 20 minutes after the boiler stopped firing and they were cooling down. My guess was it was the contraction/expansion of the radiators working against the wood floors.

My first attempt of quieting them down was to simply move the radiators in whatever direction they would move on the floor. That didn't work at all.

I decided to try to put something slippery between the floor and the radiators. I thought long and hard about what I could use and tried a plastic milk jug. No, I didn't put the whole jug under the radiator but I cut small squares of the plastic to put under the radiator feet. I put two squares under the feet of each of our radiators.

Since doing that a couple of weeks ago we have not heard any noise from the radiators. My wife is amazed at my ingenuity.  :-)



  • mskalinin
    mskalinin Member Posts: 13

    We have had that same pop on a few of our radiators, we will give this a try if it persists after the new boiler goes in. Are you talking plastic milk just (like the gallon ones?) or the cardboard ones?

  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,849

    Plastic milk jugs are made of polyethylene, which has a low coefficient of friction. Unfortunately it's not cross-linked, so it will stretch and distort over time. It will also tend to keep slipping out from under the feet, so you'll have to keep after it. But the material is free, and the radiator will let you know when it needs attention.

    By the way, this usually works because it raises up the radiator enough to correct the pitch of the connected supply piping. I've gotten the same results using tongue depressors.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • ryanr256
    ryanr256 Member Posts: 49

    I used the plastic milk jugs. I will watch to see if the tabs deteriorate.

    I don't believe it's a pitch problem. We don't have any water hammer or cold radiators when the boiler is steaming. Matter of fact we have the opposite. The radiators are hotter than they have ever been. The house seems more evenly heated and, prior to the fixes, we did have severe water hammer. It was so loud I'm surprised the neighbors didn't complain.

    One of our fixes was to correct the pitch of the radiators and mains. We also redid the near boiler piping to get drier steam. I think we were successful with our efforts.

    It wasn't until after we changed things that the radiators started making this noise. And, it would happen well after, 20 to 25 minutes, the boiler stopped firing.

  • Noisy Rad

    When I took my radiators off to replace the valves, I added those felt pads for furniture. After sanding and painting them I stuck them on the bottom and it worked really good.
  • SWEI
    SWEI Member Posts: 7,356

    aka Teflon does not degrade with heat or oxygen the way PE does.

  • ryanr256
    ryanr256 Member Posts: 49

    Thanks for the link. I used what I had. I will look into the teflon.

This discussion has been closed.