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Finally took the low pressure leap.

Ok, I am an amateur.  However, I’ve read one of Dan Holohan’s books, and am on the board of my 98 unit building.  So I’ve interfered in the delivery of our single pipe, 5M BTU boiler, steam heat.  Today we called the tech out, and reduced the pressure from a 4psi target (started modulation at 4psi) and 6psi cutoff to a new, lower pressure of 2psi modulation start with 3psi cutoff.  I’m seeing a small reduction in the amount of heat delivered per cycle.  Am I going to be sad when I see the bill, since I seemingly now may need to run the cycles a bit longer?  The DH book seems to say no, but I’m just a bit nervous since I stuck my nose in an area that isn’t my expertise.  What do you think?


  • Jamie Hall
    Jamie Hall Member Posts: 22,972
    Courage. And hang in there.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • kcopp
    kcopp Member Posts: 4,397
    If the Empire State building can run off 2psi your house also can.... also from Dan.
  • ethicalpaul
    ethicalpaul Member Posts: 5,628
    In for a penny, in for a pound, might as well set the cutout for 2psi and see how that goes.

    You won't spend more money. Before you were burning tons of fuel to get the pressure up for no benefit.

    When you say "small reduction in amount of heat delivered" what do you mean by that?
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,768
    No guts no glory.   I learned most of what I know climbing out on a limb and 'seeing what happens."  I commend you.  The less you to FORCE the steam (high pressure) , the better it works. It does what IT wants to do naturally. Like a Wild Mustang...Our job is to get out of its way and let her run free!  Mad 🐕 Dog
    Long Beach Edkcopp
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,188
    edited January 2023
    If you are needing higher pressure to complete steam distribution, you need better venting. The boiler's producing steam faster than the air can be vented.
  • vhauk
    vhauk Member Posts: 84
    the we get most, if not all of our heat in a steam radiator from the condensation of steam, which means the steam must give up its latent heat of vaporization. So the most efficient pressure is enough pressure along with heat energy to keep the steam steam until it gets into the radiator. There is a tremendous amount of heat energy in a pound of steam. Not very much more in a pound of steam heated past it’s boiling point. 
  • Charles7540
    Charles7540 Member Posts: 4
    Thanks all - I’m waiting and watching for now. You’ve reassured me that I haven’t done something wildly reckless. I have another question, but will open a new thread for neatness. Thank you all!
  • leonz
    leonz Member Posts: 1,055
    Tell us about the venting situation with this heating system please.
  • gfrbrookline
    gfrbrookline Member Posts: 753
    edited January 2023
    Now that you lowered the pressure how is the heat distribution six days out? What do your main vents look like? Even if your mains are good I am going to guess you are going to have to change a bunch of rad vents to rebalance. If your system was set at that high I am guessing you have a bunch of vents that are stuck closed.
  • Charles7540
    Charles7540 Member Posts: 4
    Exactly. We had many, many vents broken. The super and I ran around changing them as fast as we could get them delivered. Main venting is good, we did that before we lowered the pressure. 4 Gorton #2s per branch. So far it seems to be working. The heat timer is running at higher ‘letters’ than it used to, but I’m hoping the modulation and cycling will offset the cost of longer ‘call for heat’ sessions. We have also reduced our heating cycles from 110min to 90 min. I’m hoping to get the Jan gas bill and determine therms per degree day, and then I’ll do the same for last year’s bill, and see what I’ve got.
  • ethicalpaul
    ethicalpaul Member Posts: 5,628
    I would say the greatest benefit will be in the performance of the system--less hissing, less spitting, less broken vents, less water level issues.

    The bills will be what they are going to be, but your system is going to work better all around
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el