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Radiator noise

NFERNFER Member Posts: 17
1pipe Steam system
Every night at 5am when the heating cycle starts for the first time the pipe below the floor that connects to the bedroom radiator makes a bang noise. It is only one but very loud, like an expansion noise. It seems it happens when the pipe is getting hot. But it does not happen at the following cycles.
Have you ever deal with this issue? What can I do?


  • FredFred Member Posts: 8,423
    If it's a loud bang, it could be that the horizontal pipe under the floor has settled a little and the pitch is now in the wrong direction so that it is holding a little water, causing water hammer. See if you can raise both ends of the radiator about a half inch or so and then repitch the radiator so that the vent end has a slight pitch back towards the valve end. That may raise the horizontal pipe under the floor enough to allow it to drain.
  • nicholas bonham-carternicholas bonham-carter Member Posts: 8,137
    Can you set a constant temperature, so the pipe will not have to expand and contract so much?--NBC
  • NFERNFER Member Posts: 17
    Thanks for the response.
    I have water hammer in other radiator and this noise is different. It sounds like the pipe is pushing the hardwood floor or subfloor when the pipe raise to the floor hole.
    How can I solve this?
  • FredFred Member Posts: 8,423
    If you think it is the pipe rubbing against the wood floor, see if you can wrap a slice of a plastic milk carton between the pipe and the flooring. Sounds strange, I know but that piece of plastic will allow the pipe to slide and it is rated at well above 212 degrees.
  • JUGHNEJUGHNE Member Posts: 6,965
    Is the basement ceiling open that you can see the pipes?
    If the floor hole is tight to the pipe you might be able to "whittle" some wood away so the pipe is free to move. Some cut milk jug material so as to act as a slip guide surface to reduce friction.
    Sometimes the rad has been pushed sideways so the pipe is not centered in the hole and rubbing on one side.
  • NFERNFER Member Posts: 17
    No, I only have access from above. I will try the plastic milk trick tonight. I am not sure to have enough room to insert the plastic .
  • NFERNFER Member Posts: 17
    It worked!
  • FredFred Member Posts: 8,423
    @NFER , That's great.
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