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"Dripping sound" heard in wall when furnace turns on

A tenant of mine recently wrote me:

The issue started a couple days ago when we turned the heater on. As the heater goes through the cycle of being on to heat the place up and turning off as it gets to the right temperature, there is a dripping sound that we hear in the walls of the bedroom when it kicks on. The dripping will start when it turns on then fade after a minute or 2. There are 2 spots in the wall where we can hear it: in the wall that touches the main hallway upstairs and in the wall of the closet that touches the washer/dryer nook.

The tenant also provided a recording of the sound: https://streamable.com/j2aqca.

Is this just the sound of metal expanding? Should I be concerned? Should I have someone come out to take a look? Thanks in advance!


  • delcrossv
    delcrossv Member Posts: 742
    edited October 2021
    Sounds more like expansion than dripping to me. "clicks"
    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
    Erin Holohan HaskellJUGHNErandomuser0285
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,526
    I think it’s an expansion sound. 
    Retired and loving it.
    Erin Holohan HaskellJUGHNELarry Weingartenrandomuser0285
    JUGHNE Member Posts: 11,061
    Assuming this is hot water heat; if it was a leaking drip, it would always "drip" as the system is always under just about the same pressure. Some wet spot would show up somewhere.
    You could shut off the water supply and see if the pressure drops.
    Turn the water supply back on unless you have a low water cut off control or monitor the system almost daily.
  • randomuser0285
    randomuser0285 Member Posts: 2
    Thanks to all for your replies. @JUGHNE, it's not hot water heat, just the electric furnace heating the house.

    Is there anything that can be done to mitigate / dampen the sound, assuming it's expansion? My tenant complains that it's loud enough that it's annoying at night.
    JUGHNE Member Posts: 11,061
    So sheet metal expanding?
    Possibly disconnect part of the elements.
    Or a 2 stage tstat.

    Or get a white noise machine.
    A fan running works for my wife.
  • JakeCK
    JakeCK Member Posts: 1,356
    I've found that as long as I know what a noise is I can generally ignore it. Maybe just explain that it is the ductwork expanding as it heats up and is nothing to worry about?

    You should hear the bangs a bunch of iron pipe can make against wood framing when it swings from room temperature to 160f+.