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  1. #1
    Join Date
    Feb 2009
    Location
    Canada
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    6,876

    Need pneumatic timer

    I am looking for a mechanical wall mounted timer to switch a room from occupied to unoccupied. Right now we have a pneumatic switch that people have no idea how to switch to unoccupied once they leave the room.

  2. #2
    Join Date
    Mar 2009
    Location
    Several Miles from Sane
    Posts
    1,472
    Do you have Day/Night (dual pressure) main air for switching to the t-stat ?

    They used to make a pneumatic crank timer that may be what you are looking for. I don't know if they are still available.

    Need more specifics on the existing eqpt./controls.
    If sense were so common everyone would have it !

    All opinions expressed are my own. Any advice provided is based on personal experience, generally accepted fact or publicly available information. As such, it is worth exactly what you paid for it, not a penny more not a penny less !!

  3. #3
    Join Date
    Feb 2009
    Location
    Canada
    Posts
    6,876
    No Day/Night. These are some meeting rooms in inside spaces normally they are unoccupied.

    A pneumatic crank timer is just what we are looking for. We have a Honeywell TP970A stat that is to control pressure switches for two stages of electric heat. The VAV would be either at minimum or maximum depending on the timer.

  4. #4
    Join Date
    Oct 2005
    Posts
    327
    M.H. Rhodes used to make a pneumatic crank timer but stopped some years ago. I haven't been able to find an equivalent. Too bad, since it was perfect for some applications. An electric timer and EP relay might be your next best bet.

  5. #5
    Join Date
    Feb 2009
    Location
    Canada
    Posts
    6,876
    We were going to go to an electric timer and EP relay but I like to keep things dumb and simple if I can. Oh well, that is what you get when technology advances.

  6. #6
    Join Date
    Mar 2009
    Location
    Several Miles from Sane
    Posts
    1,472
    I found 2 of the pneumatic timers (used) in a box of old stuff. I'll test em out monday and let you know if they still work.

    Is your email in profile, if not put it there, please ?
    If sense were so common everyone would have it !

    All opinions expressed are my own. Any advice provided is based on personal experience, generally accepted fact or publicly available information. As such, it is worth exactly what you paid for it, not a penny more not a penny less !!

  7. #7
    Join Date
    Feb 2009
    Location
    Canada
    Posts
    6,876
    Thanks for the help CCIKelly. I am looking for more than ten and was hoping to find if someone still makes them. Otherwise my boss may not too keen on going that route. More than likely we will go to an electric timer and an E/P.

  8. #8
    Join Date
    Aug 2006
    Posts
    2,609
    About twenty-five years ago I put a bunch of Robertshaw spring wound pneumatic timers in where an occupied / unoccupied wall switch was. Five years ago I tried to find them for a job, did an exhaustive search for them and found nothing. I think they were too simple and too cheap


    Edit: Found the old Robertshaw P/n N100 -4200 Pneumatic Time switch, Manual W/Hold 12 Hr, Supplied with N4-109 nipple for 1/4" tubing
    P/n N100 -4200 Pneumatic Time switch, Manual W/O Hold 12 Hr, Supplied with N4-109 nipple for 1/4" tubing
    Last edited by madhat; 04-18-2009 at 01:05 AM.

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