Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Noise Inside Boiler at The top

We are running oil-fired one pipe steam at the house.  The high water content boiler was installed in 1932,and has given really no trouble.  Piping is the same since install.  For the last 4 or 5 years, about 4 minutes after start up, there is a sound coming from the top of the boiler, that sounds like 10 marbles are rolling around in there. This is before boiling. The sound gradually gets less over a 5 or 6 minute period, and then goes away.  I do add a can of anti-surge powder at the top of the season.  I'm just wondering if anything is coming apart inside. Thanks.


  • save the powder for baby's bottom

    has regular maintainance been preformed? you maybe overfired or over pressured.check your pressure, and keep it under 16 ounces.  alternatively, there may be solids [old anti surge powder !!] at the bottom which are causing percolation. a blowdown of the boiler could get these out, or you will need to open the bottom tapping to rake them out. the result is greater longevity, and economy--nbc
  • lutorm
    lutorm Member Posts: 78
    Our boiler does this too, I think

    If it's the same thing we're experiencing, it's the same sound that comes from a water kettle or a pot on the stove when it starts heating up, but long before boiling and without any associated bubbles. I've never understood what this sound comes from (microscopic bubbles that form and implode?), but since it seem ubiquitous to water heating equipment, I didn't think there was something you could do about it.
  • Jamie Hall
    Jamie Hall Member Posts: 20,816
    Lutorn has pretty well got it --

    the sound comes from steam bubbles forming on usually microscopic sharp projections on the metal, and then collapsing when they move away into the cooler water.  Nice description of it, by the way!

    I am not too surprised to hear about it in an older boiler, as the sharp projections are mostly on scale crystals and other odd deposits on the water side of the metal.  Short of figuring out a way to get all the scale off, I'd say to live with it.  The downside is that it does indicate scale -- which will reduce the efficiency of the boiler.  How much?  Who knows.  Is it an issue with a boiler installed in 1932?  If that puppy is keeping you happy, no.  But I would imagine you could save some fuel with a more modern boiler...

    Don't put anything in the boiler to try and stop it.  In fact, I don't really recommend putting anything other than water in a residential boiler, except for the occasions when you are deliberately trying to clean it.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • cremfe
    cremfe Member Posts: 5
    OK. Sounds Good

    Yes, the furnace gets yearly maintenance.  Pressure at cut out is about one pound or less. Will cut out the powder.  Yes, will live with it. Burner is also ( not as ) old , low rpm , but QUIET. Thanks all.
  • percolation

    the percolation i was talking about, is the entrapment of boiling water between the metal boiler section, and a layer of calcium scale, which makes a popping noise. as this usually below the waterline, it probably could be removed through the lower large tapping of the boiler. ask your installer if this is desireable, or just opening a can of worms. he could look for any pinhole leaks which have been sealed with scale, but noting any "stalagmites" protruding into the fireside of the boiler. if they are there, best not to disturb them.

    has the boiler been blown down through the main drain regularly?--nbc 
  • cremfe
    cremfe Member Posts: 5
    Blow Down of Boiler

    The boiler is blown down weekly at the low water cutoff and also at the valve mounted 6 inches off the floor at junction of wet-return and boiler feed pipe.  Not sure what that is called.
This discussion has been closed.