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  1. #14
    Join Date
    Apr 2003
    Location
    St. Louis
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    Quote Originally Posted by BBeerme View Post
    Positive or negative building static is one of the easiest things in the world to check. You already own the instrument. Let me find the photo . . . I know right where it is . . .

    All you need is this highly developed instrument, and an outside door.
    Whats OAD and RAD ? Building static sensors need to be in a area by the main doors. Your running -.8" static doors would be like a wind tunnel and hard to open if they pull to open.

  2. #15
    Join Date
    May 2014
    Location
    Bay Area California
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    Quote Originally Posted by servicefitter View Post
    Whats OAD and RAD ? Building static sensors need to be in a area by the main doors. Your running -.8" static doors would be like a wind tunnel and hard to open if they pull to open.
    I guess you did not see the photo that I posted.
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

    I use 56% silver on everything except steel.

    Did you really need the " If you were a real tech " ??

  3. #16
    Join Date
    May 2014
    Location
    Bay Area California
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    For what it is worth, I have seen multi-story buildings where the only access to the outdoors was the lobby, and Floors above that we're causing pressure issues on the first.
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

    I use 56% silver on everything except steel.

    Did you really need the " If you were a real tech " ??

  4. #17
    Join Date
    Apr 2003
    Location
    St. Louis
    Posts
    1,248
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    Quote Originally Posted by EffortPLG View Post
    Hello All,

    I'm new to the forum, but glad to see the technical expertise that exists here.

    With that said, I have a fairly technical question about IAQ.


    I am the facility manager for a museum in Chicago. The building has VERY tight parameters that mus be met, e.g. 46-50%RH and 68-72degrees.

    The main problem I'm having is the building static pressure sensor controls the Outdoor Air Dampers. The sensor is all over the place with it's readings, and most days the readings indicate that the building is in a negative pressure, although I don't believe this to be the case.

    I've seen quite a few things about how to measure the building static pressure, but it seems that one end of the manometer tubing tests outside, while simultaneously checking the inside of the facility with the other end. I've done "before coil, after coil" tests to see the condition of the coil, but this is the first time that I've been in the position of being responsible for building static pressure, and how it's supposed to be read.

    I have about 8 years of in the field HVAC experience, mostly commercial.

    With all that said, here are my problems:

    - Building Static Pressure = (-).25 most of the time
    - OAD = 100% open most of the time
    - RAD = vary with operation, but (OAD + RAD = value not always 100+%). The OAD and RAD(or mixed air damper) are separate entities.
    - Condensation collecting inside OAD duct work, right near register on outside of building. (rain isn't possible)

    What I think:
    - What I think is happening is that the static sensor is causing the building to become over-pressurized, and the over-pressurized air in the building is leaking outward(somewhat) through the OAD ductwork...at 68-70 degrees and 45-47%RH. Because my return air is 68, with this humidity, and it's 30 degrees outside...(insert psychometric chart)I feel that i'm hitting saturation point within the OAD duct work and my 45RH% is increasing to 100% with the temperature drop...leaving the condensation in the duct work right outside the OAD register.

    Any threads already made on this, or does anyone have any ideas for me?

    Cheers,
    Effort
    Just wonder how old the building is because i started up a new addition to the St. Louis art museum and the Chicago general contractor was starting another museum in your town. Commissioning was brutal but their was going to be irreplaceable art. Sat empty 60 days just to make sure everything worked while they cleaned the building and built displays. There is no way that i would make a change by myself because if something screws up and something got ruin you would be gone.

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