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What is this?

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tylerjgardner
tylerjgardner Member Posts: 14
in Strictly Steam

Doing a steam boiler install and my co worker asked what this is. I said "no idea lol". Its a two pipe system and this is at the end of the re

20260325_104236.jpg
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turns.

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 27,355

    Dunham Return Trap for Dunham vapour steam system. It's in The Lost Art — look it up.

    That system should be controlled with a vapourstat running at a cutout of 8 OUNCES per square inch or less.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • tylerjgardner
    tylerjgardner Member Posts: 14

    Interesting. What are the consequences if I run it at 1.5 oz? The old system had the standard pressuretrol (same as this new system)

  • ethicalpaul
    ethicalpaul Member Posts: 8,779
    edited 5:17PM

    I think you mean your pressuretrol is set to 1.5 psi

    That is way too much especially since most pressuretrols that are set to 1.5 actually cut out between 2 and 2.5 psi

    (8 oz is .5 psi)

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • tylerjgardner
    tylerjgardner Member Posts: 14

    I mean 1.5 psi

  • KC_Jones
    KC_Jones Member Posts: 5,934
    https://forum.heatinghelp.com/discussion/comment/1892836#Comment_1892836

    If you sized the boiler correctly it shouldn't get to 1.5 psi, so it shouldn't matter. The vaporstat or pressuretrol are pressure safeties. On 2 pipe the sizing is extremely critical, I feel it's critical for all systems, but the 2 pipe are typically more sensitive to pressure, which is a function of boiler sizing. How did you size the boiler?

    I agree with Jamie though, it should have a vaporstat to ensure it doesn't have a chance of getting out of hand.

    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • tylerjgardner
    tylerjgardner Member Posts: 14

    So yeah I would LOVE to install a vaporstat, but the salesman won't want me to get a $500-600 part for this. Also the salesman sized this boiler- you guys are gonna love this- "the old one was this size so I got the same size boiler for this zone". Theres a lot of things I can see wrong with this install, but unfortunately I was told to just "slap in it exactly how the old was was". Im beginning to realize that the company i work for is the "knuckleheads" the Dan Holohan warns homeowners about lol.

    ethicalpaul
  • Jamie Hall
    Jamie Hall Member Posts: 27,355

    You ask the consequence of running the boiler up to 3 times the desired pressure.

    It won't heat as evenly (and indeed may be difficult or impossible to get anywhere near balanced). It may use more water than it should. Components such as radiator traps and the main vents will fail much sooner. It will use more fuel than it should.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    tylerjgardner

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