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  1. Replies
    4
    Views
    1,114

    In a situation like this I certainly would not...

    In a situation like this I certainly would not recommend lowering the space temperature set point. If the unit will allow you to place the fan on continuous run mode I would try that first. Keep the...
  2. Replies
    1
    Views
    759

    My thoughts are you are correct on your wild...

    My thoughts are you are correct on your wild guess. With a bunch of air bypassing, but with the system still calling for cooling, the supply air temperature is likely to drop well below normal...
  3. Technically, general air changes have no...

    Technically, general air changes have no stipulations regarding filtration. If the room happens to be a negative pressure room, the general air changes are calculated by the exhaust leaving the room....
  4. Replies
    20
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    1,907

    I want to give kudos to BenControllin here. These...

    I want to give kudos to BenControllin here. These are contract documents we are talking about here, and every avenue must be taken before any changes are made.
    Based on the information provided, I...
  5. Replies
    10
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    1,019

    heatingman, I can appreciate your desire...

    heatingman,

    I can appreciate your desire to get more involved with controls. I wish more 'mechanical' guys did. Dead serious. But as a 20 plus year test and balance technician I cannot help...
  6. Replies
    21
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    32,771

    The typical CO2 set point I see is 900-1000 ppm....

    The typical CO2 set point I see is 900-1000 ppm. You have measured a high of 775, and my high was around 650. In both instances we would be able to maintain a level between 900-1000 with additional...
  7. Replies
    2
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    1,338

    I have balanced many "pool packs", but have only...

    I have balanced many "pool packs", but have only witnessed a few that actually worked in all load conditions. Higher end chilled water/ hot water/ electric reheat systems in upscale hotels and such....
  8. Replies
    21
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    32,771

    The industry standard that we use is 400-450 ppm...

    The industry standard that we use is 400-450 ppm CO2 for fresh air. Technically it is 392 ppm. And although I have tested 'fresh' air at higher levels than that, never have I ever seen it above 650...
  9. Replies
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    32,771

    If the task is to simply lower the CO2 to below...

    If the task is to simply lower the CO2 to below 1000 ppm and maintain that concentration, with no regards to temperature or humidity, I think it would be rather simple. A 100% outside air variable...
  10. Replies
    14
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    2,040

    Many single phase motors have changeable...

    Many single phase motors have changeable rotations. There are several spade connectors under a removable wiring plate on some. Change this spade to here, move that spade to there and bingo ... it...
  11. Replies
    15
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    3,042

    In your opinion, what would be the benefit in...

    In your opinion, what would be the benefit in running a flex only duct system?
  12. Replies
    15
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    3,042

    Sheet metal has been the industry standard since...

    Sheet metal has been the industry standard since the beginning of the industry. Sheet metal with flex take offs came around later. Total flex is the lazy mans way. Not to say that it will not work,...
  13. Replies
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    2,147

    Although probably out of your price range, I...

    Although probably out of your price range, I would suggest a Shortridge ADM with an airfoil for velocity readings. It is the least angle sensitive device I have used. For a cheaper option I would go...
  14. Replies
    9
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    2,042

    Not knowing the application (type of facility),...

    Not knowing the application (type of facility), the amount of required outside air and calculated loads it is hard to say. I am no engineer, but at nearly 4 cfm per square foot (based on 400 cfm per...
  15. Replies
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    751

    That seems like a large delta to me. Assuming...

    That seems like a large delta to me. Assuming your longest duct run is 100 feet, and your air velocity is 500 fpm, it takes 11 seconds from fan to grille. That is about one degree per second. That is...
  16. ChippyTX, Not to sound like a jerk, but...

    ChippyTX,

    Not to sound like a jerk, but either you can afford to keep a reasonably even temperature throughout your house or you cannot. If you can, set the T-stats at the same temperature and...
  17. Replies
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    2,342

    That is a very awkward way to introduce make up...

    That is a very awkward way to introduce make up to a pressure critical building in Florida. Actually, that is awkward no matter where you are at, but especially in Florida. Based on the picture, I am...
  18. Replies
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    6,643

    In this day and age of commissioning and LEEDS...

    In this day and age of commissioning and LEEDS certifications, the 'drive by' balancing or 'Denny's reports' are a thing of the past. Those who 'pencil-whip' reports these days will not last long.
    ...
  19. Thread: cfm

    by tnhikr44
    Replies
    14
    Views
    1,706

    just_opinion, 1. As I stated previously,...

    just_opinion,

    1.
    As I stated previously, size and velocity are relative. On that return duct you mention the typical velocity will be somewhere between 500 f.p.m. and 1000 f.p.m. on nearly...
  20. Thread: cfm

    by tnhikr44
    Replies
    14
    Views
    1,706

    just_opinion, Not trying to be an ass, but,...

    just_opinion,

    Not trying to be an ass, but, in my opinion you have it completely backwards.

    1. Size and velocity are relative. If the system is large the ductwork is large... but the velocity...
  21. Replies
    4
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    2,874

    Madtrumpeter, By a high velocity sysyem do...

    Madtrumpeter,

    By a high velocity sysyem do you mean that there are small supply grilles installed, creating a "jet"effect at the grilles? Or are you talking about small ducting (due to restricted...
  22. Several people have mentioned economizer...

    Several people have mentioned economizer controls, which is
    an important factor in regards to energy consumption. But no one has really mentioned required ventilation. In most commercial bldg.'s...
  23. Replies
    15
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    1,851

    Perhaps I am misunderstanding you, but if you are...

    Perhaps I am misunderstanding you, but if you are truely going to use an automated system you need sensors, not T-stats. That is assuming that you want your temperature controls functioning via a...
  24. Replies
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    1,133

    You could, but I am not sure it would be received...

    You could, but I am not sure it would be received well. In the past we have somewhat clashed in regards to sequences of operation and such. The casino hotel job in Cherokee comes to mind, along with...
  25. I think this is a very valid point and should not...

    I think this is a very valid point and should not be overlooked. As previously pointed out, "over" filtration will cause reduced airflow, which in turn will cause reduced performance of ANY filtering...
Results 1 to 25 of 44
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