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Sight glass jammed in tight, is it supposed to be jammed against seals or not?

Anne_5 Member Posts: 27
Hello everyone. I am having discussion with someone working on my boiler about the sight glass. He believes it should be jammed in tight with pressure put on it to keep the seal. I don't think it should be. Please advise. Thanks.
It's supposed to knock. It's steam.


  • KC_Jones
    KC_Jones Member Posts: 5,737
    The boiler runs at very low pressure so it doesn't take much to keep it sealed. It's a bit confusing to me what he means by "jammed in tight". There are nuts that keep it tight so there really isn't any "jamming" for this.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • nicholas bonham-carter
    He should know when it is tight enough when there is now leakage from the bottom and top nut.--NBC
  • Fred
    Fred Member Posts: 8,542
    There are gaskets that go under the nut at top and bottom. As long as the glass is long enough to be sealed by the gaskets, it won't leak. If it does, he needs to tighten the nuts a little more to compress the gaskets a bit more.
  • Jamie Hall
    Jamie Hall Member Posts: 23,280
    And a sight glass which is really jammed in tight may very well crack. Not what you want...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England