Problem: hearing clicking metal noise when water-based heating is on. Because this sound travels so quick, it was very hard to find the spot, but finally found it - right below the outlet.

Opened the wall, here it is: enter image description here enter image description here

Black pipe in the back: water-based heating.

The three pipes at the front: electrical.

Note that the middle pipe is not straight - maybe a problem during construction? instead of side-by-side/aligned with the other two pipes, the middle pipe has a bend going a little behind. It is touching (ou super close to) the heating pipe and causing the clicking noise as the heating pipe expands/vibrates.

What do you guys suggest? For example:

  • Just putting something (insulation) between the middle electrical pipe and the heating pipe to stop the clicking noise?

  • Cutting the middle pipe and installing a Z join (not sure if there is enough space).

All ideas are welcome. Thanks!

  • 1
    I think I would try stuffing some insulation in there and see if it would quiet things down, trying to put a offset in old construction can open a big can of worms.
    – Ed Beal
    Commented Mar 28, 2019 at 18:17
  • @EdBeal Thanks, "offset" means rerouting the original pipe by cutting it and joining with a new one that goes to the right direction (by aligning it with the other two)? What would be problems you foresee?
    – igorjrr
    Commented Mar 28, 2019 at 18:52
  • Cutting into old pipe you can find pipe walls that crumble. Threading and a union would be the only way I could to do it and I am not sure if that is legal. I don't do heated piping in my state that requires a licensed pipe fitter. I have done a lot of repairs on conduit and cutting in the middle of a run is tough. Plus you don't have much room to work with.
    – Ed Beal
    Commented Mar 28, 2019 at 20:05
  • @EdBeal I understand. If there is no space to stuff some insulation, what would be your second option, please?
    – igorjrr
    Commented Mar 28, 2019 at 20:14
  • If there is room in front of the conduit I would use a hickey and tweak the conduit but it looks to be in rough shape but I would try that before messing with a heating pipe but I am an electrician and conduit is something I feel comfortable messing with. I am not sure if even a short hickey would fit in there.
    – Ed Beal
    Commented Mar 28, 2019 at 22:22

2 Answers 2


A little window and door, low pressure expanding foam will do the trick. Be very careful around those pipes they are in very bad shape. Don't pry or push on them. You are going to need a complete overhaul of your heating system if they are representative of your system. I'd start putting money away if I were you.

Don't use the regular expanding foam. It creates enormous amount of pressure.

  • The conduits (electrical pipes) are in bad shape but the heating pipe (black pipe in the back) doesn't look bad (to me!). However you wrote about the heating system, but they are the electrical pipes. Did you invert or I understood wrong?
    – igorjrr
    Commented Mar 28, 2019 at 21:43
  • Oh yeah I got it backwards, the spray foam trick still works. Luckily it's not the hydronics. That would be a very expensive ordeal.
    – Joe Fala
    Commented Mar 28, 2019 at 21:48
  • Thanks for clarifying. One more question, I'm sorry: this foam expands and becomes solid, correct. Won't it also cause noise, which is the original problem described in the question, just a different kind of noise (between pipe and foam instead of heating and electrical pipes)?
    – igorjrr
    Commented Mar 28, 2019 at 22:38
  • It doesn't become solid like a rock but it does firm up quite a bit. My plumber showed me the trick. I've got a rental property that I'm going to gut soon. Current tenant was complaining about noise from the plumbing stack. I just poked 8 holes and injected spray foam. Problem solved. In your case if it doesn't work you can just remove it. You can try lots of different things because it's open and right in front of you.
    – Joe Fala
    Commented Mar 28, 2019 at 22:59

I would first try to wedge some solid insulating material between the pipes, the heat pipe although large may move a bit, I doubt the conduit will be easy to move as it looks to be going into concrete. My second option would be to find / borrow a short hickey. A hickey is a pipe bending tool most folks use a 90 degree model but a short hickey only bends to 30 degrees but they will fit in tighter spaces. I would be cautious as the conduit looks very rough, if it's rigid steel the walls are fairly thick and much tougher to bend than EMT or thinwall. I don't think I would use spray foam because as the pipe moves it will cut through the foam and a couple of months after repairing the wall the noise may return. When I think of something that you may have like a old pot holder I think that may do the trick.

  • Thanks! Being an electrician, if you see that you can't bend because the conduit is too old for that: let's say you try and it breaks, or you don't even try because you know it will break, what else would you do? Cutting it and joining with a 90 degree new conduit moving away from the heating pipe is possible? Otherwise what, demolish the building because one pipe was installed wrongly (kidding)? I'm trying to find an answer if these simpler fixes don't work.
    – igorjrr
    Commented Mar 29, 2019 at 19:10
  • Rigid pipe can be repaired but it is hard to do. there are split couplings and 3 piece couplings that can be installed split couplings the wire can be left in place but if more than this is needed the wiring will need to be pulled back to add the coupling and longer piece of pipe. I as I originally said I would put an insulator between the pipes.
    – Ed Beal
    Commented Mar 30, 2019 at 0:13

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