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Renter losing sleep over clang of 2-pipe radiator

Victoria Member Posts: 1
Hi all- 

     Been having problems sleeping as the radiator in my bedroom has begun clanging multiple times a night. To keep the bedroom and my husband cool, I keep the radiator all the way off, closed tight.  It is a two-pipe system.  

The clanging is at the beginning of the heating cycle; the hammering occurs at the intake pipe up to the closed valve. Sometimes the radiator in the hallway clangs first (which is also closed). If I open the valve all the way, the clanging stops immediately.  This is however inconvenient as I have to do it 4-5 times night.  

     Leaving the radiator on is not an option, as the room would become a sauna, and my husband would go sleep on the couch.  Asking the landlord to turn off the heat is not an option, as I live above a grocery store that uses heat to offset their refrigerators' cooling year-round. (I knew about this beforehand, and the rent I pay takes it into account.)

     Is there anything I can do to stop the clanging, like insulating the intake pipe in my bedroom?  Any idea of what may be causing the hammer?  Or should I talk directly to my landlady?  How can I intelligently describe the issue to increase the chances of it getting fixed?

Thanks in advance, 



  • Alan (California Radiant) Forbes
    "In any steam system,

    the condensate is supposed to drain by gravity back to the boiler or condensate receiver.  If water lays in the pipes between firing cycles, steam will pick it up and drive it into the first available fitting.  Water hammer from bad pipe pitch usually happens when the system first starts.  Steam will also rapidly condenseover a puddle of water causing the water to snap violently up into the partial vacuum left by the condensed steam.  The proper pitch for parallel flow steam mains is one inch in 20 feet. For counterflow mains, it's one inch in ten feet. Check the pitch with a line level."

    Quoted from "A Pocketful of Steam Problems (With Solutions)" by Dan Holohan
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • Brad White
    Brad White Member Posts: 2,398
    Insulate the pipes

    Victoria, you may or may not have ill-pitched piping and if you do, that is not something that you yourself would correct. (Maybe you would- Why would I sell you short??)

    But insulating bare pipe is an inexpensive way to lessen sudden steam collapse which in turn can make for some interesting noises.

    An analogy I use is to imagine a pound of steam at about 24 cubic feet, about the size of a Sub-Zero refrigerator, collapsing in an instant into something the size of a Rubik's Cube.

    But to be effective, you should be insulating more piping than just that above your floor, it should go way back to the boiler. Have a talk with your landlady. Insulating the piping (perhaps laid bare by asbestos abatement), can save her energy dollars, uncontrolled heating and losing a good tenant.

    My thinking continues to your point that when you open the valve, the clanging stops immediately. That leads me to think that the valve as a dead-end is also seeing water carried by the steam (from other bare pipes not yet warmed up), to a stopping point. Of course, I am not there, so have to guess.

    You might also ask at what pressure they run the system. It well could work on less than a pound of pressure yet some are set at 3 or 5 lbs. when eight ounces would do it. High pressure cannot help.

    But insulation is short money regardless and setting the pressure down as low as you can, costs nothing.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
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