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Boiler pressure Question

New gas PENNCO 1606 boiler installed last fall.

I have worked on adding main vents on the new system all year to include 2 Gorton#2's/2Bigmouth vents on main run, and 3 Gorton 1's on shorter main run(due to height issue)

Replaced all vents on every radiator to vent-rite adjustable and have spent considerable time adjusting those to ensure all radiators heat the same which they now do throughout the home.

Satisfied with the speed of main lines filling with steam and also the radiators in the home heating properly.

Pressuretrol set at .5 cut-in and 1 diff. to cut out. The pressuretrol never has shut down my system as my pressure to heat my home is on 1.5 oz per sq/in. Yes I said OUNCES

I ended up installing a low pressure ounce gauge as I never see pressure on the 0-30 as well as my 0-5 PSI gauges. (I have all 3 gauges installed and running) I lose zero water and ensure I do all maintenance myself with few exceptions.

From what I have read over this site as well as the books I have studied on the matter, steam is best moved and used with as little pressure as possible and will finds it own way.

I am questioning why pressure is so low and is anyone else having a system running like this. I see a lot of posts discussing pressure, shutoffs, etc. due to pressure which I am not seeing.

I will anticipate in the PENNA winter coming and as temps drop, perhaps I will see a rise in pressure the longer my system runs and my radiator vents close as long as my thermostat is not satisfied?

It has been running with late night temps in the high 20's and still boiler maintains the super low pressure.


  • Jamie Hall
    Jamie Hall Member Posts: 23,273
    It would appear that you are among the fortunate who have a system where the boiler is about the right size for the system and the venting is adequate.

    Yes, there are a number of people whose systems run very much in the way yours does -- the ones I care for, for instance. You just don't hear about them.

    Be happy.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • KC_Jones
    KC_Jones Member Posts: 5,736
    @ChrisJ would say measuring pressure in ounces is out of hand.  Be happy with what you have, low is good.

    I haven’t seen 1.5 ounces on my system ever, I don’t watch it continuously, but my basement is a workshop so I see it firing often, the needle just sort of shakes around under 1 ounce.

    I don’t recall the number, but @ChrisJ calculated the pipe resistance for his system and it was closer to zero than to 1 ounce if memory serves.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • neilc
    neilc Member Posts: 2,702
    it might be refreshing, holiday like, even therapeutic, if you would post a general picture of your boiler,
    one of a few, as Jamie said, sized right, operating properly, (low pressure is your goal, and friend)
    a happy holidays story , , ,
    known to beat dead horses
  • ChrisJ
    ChrisJ Member Posts: 15,660
    edited December 2021
    KC_Jones said:

    @ChrisJ would say measuring pressure in ounces is out of hand.  Be happy with what you have, low is good.

    I haven’t seen 1.5 ounces on my system ever, I don’t watch it continuously, but my basement is a workshop so I see it firing often, the needle just sort of shakes around under 1 ounce.

    I don’t recall the number, but @ChrisJ calculated the pipe resistance for his system and it was closer to zero than to 1 ounce if memory serves.

    It's been a while since I looked at this.

    Typical pressure at the boiler is 1/2oz but if the system is cool it'll run at 1/4oz.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    EBEBRATT-Ed Member Posts: 15,512

    REJOICE and be HAPPY. You must have found a contractor that knew what he was doing.

    Your boiler does not need to shut off on pressure, A couple of ounces will heat your house fine. Don't worry about the lack of pressure i's the way it's supposed to be.

    The reason you see so many post about pressure and pressure controls is because those people have boiler s installed improperly or are oversized.

    Maybe we can see some pictures to see if the contractor piped the boiler right. I don't want to take my happy words back

  • PapaDuke
    PapaDuke Member Posts: 3

    I have 400 sqft of measured steam radiators that I calculated before install using as many books I could find. I opted for the PENNCO 1606 at it pushed 479sqft as the next lower was 383sqft which I new was close however I wanted to factor pickup and piping so I went larger. (whether I had to or not)

    I added the drop header myself to assist in drier steam and reduce any carry over as I knew it was slightly oversized. Initially I saw water coming down the top of the site glass on a book normal header config the contractor did and knew from learning here that this is wet steam. The drop header fixed all of that. My risers are 3' above water line dropping about 16 to header. I also added massive venting on the long main and 3 gorton 1's on the shorter. I cannot get both to fill at the same time but the are within 60-70 sec of each other before all valves close.

    Steam will reach and close main vets within 2 minutes at 1 oz of pressure once boiler starts.

    I was initially using the round MOM valves last season but I found that I get better even heating with the Vent-Rite adjustable. The MOM and well as the VARI VALVE (the tiny sliding adjustable ones which I hate) were sometimes starving other radiators from steam so I took the advice and vented slow which was contradictory to my thought process but it actually worked.

    I dont need a vaporstat, hell I really dont use the pressuretrol. I will keep fingers crossed and keep a watch on how she acts when it gets to January when the outside is 5 degrees.

    Keep in mind, I did many of these additions/ enhancements myself after learning and reading to include the insulation, adding condensate drain valves, skim port valve,drop header, adding all my main/radiator vents and taking the time to watch water, listen to the system when it runs, skimmed many times as contractor didn't etc. Amazing what knowledge can do for yourself as well as some cheap large pipe wrenches from harbor freight. Too bad in the art of steam, it is getting more and more difficult to find someone who actually does it right so I figure I will do many things myself with some limitations.

    EBEBRATT-Ed Member Posts: 15,512

    You picked the right size boiler, the pickup factor is already figured into the boiler net square foot rating
  • delcrossv
    delcrossv Member Posts: 742
    edited December 2021
    Just to salve your fears, here's the reading off a 530,000 BTU boiler pushing a large 4 flat in 20 degree weather.

    See, you're not alone. :smile:
    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
  • dopey27177
    dopey27177 Member Posts: 887
    Looking at the piping (under the insulation) it looks quite large. There fore I think this is an older building where the radiators by todays standards are a bit over sized which may account for the building being heated at about 1/4 psig.

    Steam circulating thru the system is about 213 degrees and when filling up an over sized radiator there are enough btuh filling the mass of metal to heat the house.

    It also appears that the boiler is not to small in capacity to heat the building. Some how by luck (do not believe in it) or happenstance you were able to get it right. Remember a contractor cannot afford to play adjusting vent valves or moving vent valves from place to place. Any smart and handy home owner can do what you did if they have the patience to learn and the time to do the work.

    I love to hear stories like yours

  • PapaDuke
    PapaDuke Member Posts: 3
    Yes, it was quite interesting after having moved in what I have learned by researching how these systems are suppose to work. I have spent most of my time (and money) in venting the mains and running around the house balancing and tweaking the Emerson 1A vent rites which also were installed new. I actually tapped in a 2nd vent on a large radiator to help it heat. I have to vent slow as after experimenting with different vents and theories I have found the Emerson 1A is the only vent that seems to work best in my situation. All of the 11 radiators in the home are adjusted to heat pretty well equally now. One of the best things I did was install the drop header. Wasn't hard to do with correct measurements. That really made it difficult for any water laden steam to get into the header which I think also helped keep the pressure super low and constant.