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Pressure Gauge off Sight Glass

kredmore
kredmore Member Posts: 53
in Strictly Steam
Hello -

I am replacing my original pressure gauge (no longer functioning/troubleshooting complete to ensure it's just the gauge). Current gauge was installed connected to top of sight glass with no pigtail - see attached picture where line goes up to the left. Do I need a pigtail for protection, or can I just replace the gauge at the end (assuming sight glass water and/or lwco tube protects it? Couldn't find anything via search.



Also, my system runs greats, and I have learned over the years (a lot through this site) of how the steam systems work.

Thank you, Keith

Comments

  • BobC
    BobC Member Posts: 5,495
    A pressure gauge needs a pigtail to protect the gauge from live steam. The pressuretrol also needs one.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • kredmore
    kredmore Member Posts: 53
    Thank you. Just trying to understand how it hasn't had a pigtail for all these years (I think original to the Pennco boiler in the 1930s), and worked just fine. And why it would be run off a tee from the sight glass?
  • BobC
    BobC Member Posts: 5,495
    The original gauge may well have been steam rated, you can still get them but they will cost a lot more. The gauge can be run from anyplace that is above the boiler water and the higher up it is the better.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • KC_Jones
    KC_Jones Member Posts: 5,796
    Did the original gauge have an internal siphon? It should say that somewhere on the gauge if it did. Internal siphon doesn't need a pigtail.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • kredmore
    kredmore Member Posts: 53
    edited November 2017
    Gauge is an original Marshalltown, and don't see "internal siphon" on it anywhere. See picture. I didn't even know they made gauges rated for steam - curious now - can you suggest a brand/website for more research? I've been through most of the brands - Wika, Ashcroft, etc.

    To add a pigtail, I can add one inline (and add water) to the existing sight glass to gauge connection, or I can tee off of the pigtail that is in place for the pressuretrol.
    RomanGK_26986764589

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