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Vaporstat gets stuck

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Hello,

My steam heating system stopped working suddenly and upon further investigation I noticed that the flask with mercury in the Vaporstat Honeywell gets stuck in tilted position which prevents the system from working. When I touch or tap on the Vaporstat the flask tilts back and the systems starts working again. Please see the picture.



Any ideas on how to fix this? Do I have to replace the Vaporstat and if so which one should I get which is more reliable?
Thank you!

Comments

  • Chris_L
    Chris_L Member Posts: 336
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    Looks like you've got a Pressuretrol, not a Vaposatat.

    If the switch is not coming back on after the boiler pressure returns to atmospheric, it is likely because the "main" - the "differential" is less than zero. Try reducing the differential. If that doesn't work, then also increase the main, but just a bit (2 psi should be good.)

    The scales aren't very accurate, so you really can't put much faith in their numbers.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,544
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    1st step is to remove the control and make sure the pigtail and the pipe connections into the boiler are clear of sludge. Also check the bottom of the control.

    I just noticed that is not a vapor stat it is a regular pressure control
  • Jamie Hall
    Jamie Hall Member Posts: 23,324
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    And one other thing not mentioned above. The mercury type -- which is far more reliable than the modern microswitch type, by the way; don't lose it! -- is very sensitive to being level. Place a known high quality level across the top of the case and adjust the pigtail so it is exactly level.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JUGHNE
    JUGHNE Member Posts: 11,062
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    Those usually have a hanging pendulum in the inside back on the right side.
    There is a white dot of paint below for that to be lined up on.

    As Chris L said, maybe a little more difference between settings also.
  • Gordo
    Gordo Member Posts: 857
    edited December 2021
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    In my not so humble opinion, Honeywell's L404A-1354 was their worst pressure control commonly encountered.
    It is no longer made and good riddance.
    I would remove it, dispose of the Hg properly (hazardous waste), and install a PA404A pressuretrol instead.
    At least that is more or less adjustable to get it to work in the proper ranges.
    I would also remove that steel pigtail and replace it with a brass pigtail.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc