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How should I set THIS pressuretrol?

MotownSteamer Member Posts: 110
Hello, Scott the homeowner here. As you can see from the photos, I have taken my pigtail, pressuretrol and gauge off my boiler (two pipe steam). I replaced the horizontal piping and cleaned the pigtail. This project, along with replacing all system traps, is my attempt to get some proper performance and economy out of my system. Boiler replacement is still a year or two in the future. So, my question is.....I'd like to set my pressure correctly, assuming my other efforts restore functionality. The cover plate does not tell me if this is a subtractive or additive control. The small (top) wheel is marked DIFF. Any suggestions in setting both wheels to get 1 1/2 lbs of operating pressure? Side note.....should I replace it with a newer Honeywell unit? Perhaps the PA404A1033?


  • JStar
    JStar Member Posts: 2,752

    Set the big wheel to 0.5 - That is your cut-in pressure.

    Set the little differential wheel to 0.5 as well, or 1. That differential appears to be additive.
  • MotownSteamer
    MotownSteamer Member Posts: 110
    I get it now.....

    Ahhaaaa, I think I get it. The DIFF wheel only goes up to 3 lbs, which makes sense now that I know it's additive.

    Jeez.......mine was set by some knucklehead to cut in at 4lbs and out at 5.5! I wonder what they were attempting to overcome. I've only lived in the house for one heating season and thought it was normal for the boiler to be firing all the time (short cycling I guess). Well, the new traps should help. I'll post a picture of my main vent; it might need to be replaced too.

    Thanks for the help all!
  • bk14x32
    bk14x32 Member Posts: 13
    edited September 2011
    Comments about the Piping

    My comments are directed to your piping arrangement and material selection. Please consider the following:

    1. The vertical riser to the Pressuretrol could have a lope to prevent moisture from rising into the control. Obtain this "trap" from a Heating Supply House as it will not be found at a plumbing piping/fitting dealer.

    2. Black steel or red brass is a better choice for material than galvanized steel. The reason is general practice(black steel).
  • MotownSteamer
    MotownSteamer Member Posts: 110
    Thank you,

    yes, I have a was back on the LWCO when I took those pictures. I'll likely be replacing the boiler next year so I'll make sure everything is top quality then.
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,195
    I have a brand new one of those

    in my shop. I have no idea where we got it from it has always been on the boiler control shelf. It is nice seeing one in use out there.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
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