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Vaporstat shelf life?

My current Vaporstat (controlling a Burnham residential boiler, single-pipe steam) is now 6 years old. The predecessor failed at five years. I like to have parts on hand that are likely to need replacement soon. What is the shelf life of a Vaporstat? If purchased and stored, how will the operating life be affected?

Thanks,

Ken

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,102

    Doubt that any storage time would affect it if stored under normal temp and not exposed to high humidity or moisture.

    Ken Johnson
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,399

    If it's built properly, 100 years! Unfortunately, Honeywell had a bad batch a few years ago, but I haven't had any problems in last 5 yrs. Mad Dog

    mattmia2
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,580

    I believe that don't really have a shelf life. There is a chamber in them that will open and close the switch contacts at that set pressure (the pressure you select). As long as the seal on the chamber is intact, it should last forever. Where your old one failed was from use over time and perhaps the chamber ended up with a pin hole leak. Is your system short cycling? like opening and closing more that 5 times per hour?

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    Ken JohnsonMad Dog_2
  • Ken Johnson
    Ken Johnson Member Posts: 29

    Thanks for the helpful replies.

    I can't answer the short cycling question now, but I will set a reminder to check in November.

    Ken

  • Jamie Hall
    Jamie Hall Member Posts: 24,138

    The old mercury ones will last forever — if they are never overpressured. The newer microswitch ones should last a decade in operation (the microswitch will fail), but again if never overpressured.

    Even one serious overpressure event may kill them, but not always.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • mattmia2
    mattmia2 Member Posts: 10,390

    If the spare is stored in a plastic bag it will slow any deterioration of the plastics that might happen

  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,399

    I hoard the old mercury T 87s, pressuretrols & Vaporstats...Mad Dog

    mattmia2
  • ARobertson13
    ARobertson13 Member Posts: 46

    I have taken apart a number of vaporstats. I dropped them and hit them [Old and new] to see if they would fail or give bad inaccurate operation. They did become inaccurate and had to be adjusted but did not fail. They are basically well built. As previously stated, High number of cycling off and on would be the most likely cause of failure. I just remembered that a vaporstat in my building failed because the person who installed the heating controller was controlling the steam cut off by a relay trigged by pressure from a vaporstat. This meant that the vaporstat was tripping 18 to 20 times a day during the winter season.

    Mad Dog_2
  • Sylvain
    Sylvain Member Posts: 154
    edited October 1

    It seems micro switches have a long mechanical life

    see for example (page 5) : https://docs.rs-online.com/ae42/0900766b813e732f.pdf

    it says "up to 10 million cycles" (but it doesn't mention a minimum).

    Now I don't know if it is the same micro switch type as in a vaporstat.

    Where one uses TRVs, 20 cycles a day is not much. The electrical rating might have been exceeded by the relay used.

  • LameyerBobonov
    LameyerBobonov Member Posts: 3

    Extreme temperatures (either too hot or too cold) can affect the elastomers, gaskets, and other components inside the Vaporstat.