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steam system problem


I love in a three story house (100yr.+), converted to apartments early in its history. Each floor/apartment has it's own steam system. Our does not work well at all.

These are one pipe, cast iron, steam radiators (or so I gather), most have USAV -844 air valves, a few have much older, round valves.

1). I have a room that never gets heat: the landlord says this is because it"s at the end of the register. Does this mean the boiler is too small? Could it be something else?

2.) Most of  the radiators function inconsistently. Some times they work, some times not. Anything I can do?

3.) Best case, they only heat a coil or two, until I turn the heat way up (75deg+). Is this normal?

4.) There are only 2 that ever hiss and then at high temps. I grew up with this sort of system and remember hissing involved in a correctly functioning radiator.  

Any information would be greatly appreciated- maybe there's a previous post i could be directed to?

thank you very much.


  • dontknowsteam
    dontknowsteam Member Posts: 3

    First sentence: "live" not "love"

  • Jamie Hall
    Jamie Hall Member Posts: 22,894
    Why the correction?

    I think I like the first version better...

    Thoughts, in no particular order.

    Steam radiators do not necessarily heat all the way across.  The question isn't whether they heat all the way across, but whether they heat the rooms evenly, or the way you want them to.  If they do, fine.  If not, on one pipe steam, it's time to start playing with the vents.  (on two pipe, it's the valves or orifices).

    Both items 1 and 2 -- the radiator that never heats and the sometimes yes sometimes no -- are likely to be vent problems, or at least that's where I'd begin.  Vents do fail with time -- particularly if the pressures are too high (anything over 2 psi).  There are a number of newer vents available; others will chime in (I hope) with recommendations, as I'm not really familiar with the variations.  Gorton makes some.  So do a bunch of other folks.

    Vents don't have to hiss.  In fact, they probably really shouldn't, unless the pressures are high.  The fact that you have two which do hiss but only at high temperatures suggests that indeed the cutout pressure at the boiler may be set too high.  Wouldn't be surprised....
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • dontknowsteam
    dontknowsteam Member Posts: 3

    Thank, Jamie!
  • BobC
    BobC Member Posts: 5,471
    Pressure, venting

    "These are one pipe, cast iron, steam radiators (or so I gather), most

    have USAV -844 air valves, a few have much older, round valves"

    Those USAV air vents are known to be a problem, if they misbehave replace them with Hoffmans, Ventrites, Gortons or Maid O Mist.

    I agree that the boiler pressure should be checked to be sure it's below 2PSI, and hopefully lower. Is the water in the sight glass moving around a lot when actively producing steam? Old 0-30 PSI gauges are known to be wildly inaccurate at the low end of the scale so you might want to install an auxiliary 0-3PSI gauge.

    Also what kind of main air vent is down cellar, does that release all the air and then close when it gets hot? Be careful about using your fingers to check the outputs of air vents because that steam can burn if your not quick.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
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