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What Would Be the Consequences on Reducing the Steam Pressure?

Greetings All,

My three-story 24 unit c1915 coop building's one-pipe steam system has the boiler pressure set at 5 pounds.  It has historically been set this high by our boiler service company Hayes Mechanical here in Chicago on the assumption that the steam "has a long way to go and has to go up three stories - (~125 feet for the longest run).

In accordance with all that I have read and seen on this site, that pressure should obviously be much lower and our building engineer knows how to change it.

What would be the likely consequences of changing that pressure to say 3.5 or 2 psi?  Notwithstanding the energy savings we would achieve, would we see a greater disparity in the ability to hold space temperature in the different apartments?  If we just went cold turkey and changed it, what would happen?



  • nicholas bonham-carter
    go for it

    reduce it to as low as you can set it. my 55 radiators work better now at 3 ounces, than they ever did at 5 psi [old boiler with bad main venting]. the consequence...the gas company changed the meter because our consumption had dropped by 1/3!!

    as pressures above 3 psi will permanently destroy main vents, i suggest that you look at your venting as well, as that low pressure and very ample venting is the key. you may need vents at the top of your risers as well for the quickest, and most even steam arrival at each radiator. all the rads on the top floor should be filling with steam at the same time.

    don't forget to equip yourself with a copy of "the lost art of steam heating" available from the shop; and it sounds like your service company needs a copy too!--nbc
  • Lower the Pressure!

    Hi Bruce- Let me put it this way, the Empire State Building runs its steam system at under 2 PSI so I think you'd be okay to do the same with your 3 floors. Kidding aside, Steam systems operate better at lower pressure due to the fact that steam travels faster at lower pressure. Also building pressure when you don't need it, wastes fuel. After lowering the pressure if you had a problem it would probably been cause by high pressure (5 PSI) as high pressure is bad for radiator vents. I'd start at a 2 PSI maximum and go from there.

    It sounds to be that it would be well worth your while to get hold of a real steam pro. Since you are in Chicago, I would recommend that you contact Dave Bunnell, "Boiler Pro". He regularly contributes to this board and is high respected by the other steam pros that are on here. He's listed in the "Find a Professional" section above. Here's a link with contact information. http://www.heatinghelp.com/professional/105/Boiler-Professionals-Inc

    I think it would be well worth you while having him look at your system. There are a lot of things like new computerized controls and system "tweeks" that can make your system run more comfortably and economically and Dave Bunnell is on the cutting edge in this area and should be able to help you a lot.

    I'm just a home owner and have a house in Maine but if I lived in Chicago with a steam system, big or small, I'd get Mr. Bunnell.

    - Rod
  • jpf321
    jpf321 Member Posts: 1,568
    umm .. maybe .. just maybe ...

    Is Hayes Mechnical a fuel provider? If yes, then duh .. crank the customers up. See what happened when NBC lowered his pressure ... cut his bills by 1/3.

    Is Hayes Mechanical is simply a boiler/steam equipment service company? If yes then duh .. crank the customers up.. kill all the vents .. they'll call us when there's no heat and we can fix it for under $20.

    But maybe I'm just a jaded NY'er.
    1-pipe Homeowner - Queens, NYC

    NEW: SlantFin Intrepid TR-30 + Tankless + Riello 40-F5 @ 0.85gph | OLD: Fitzgibbons 402 boiler + Beckett "SR" Oil Gun @ 1.75gph

    installed: 0-20oz/si gauge | vaporstat | hour-meter | gortons on all rads | 1pc G#2 + 1pc G#1 on each of 2 mains

    Connected EDR load: 371 sf venting load: 2.95cfm vent capacity: 4.62cfm
    my NEW system pics | my OLD system pics
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