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  1. #1
    Join Date
    Aug 2019
    Location
    Central Florida
    Posts
    106
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    What to believe ?

    I going to jibber jabber about my thoughts on water systems . Let's say you have a chilled water system with a chiller , a pump and a half dozen airhandlers . The pressure drop on the chiller says one thing , the Venturi says another and the temperatures say something different . The same with the airhandlers , 3 ways to read the flow but they are 15% different . What would you believe and how would you report it ? What I do is I almost always believe the capacity tests by temperature . I'll report all 3 flow measurements and quantify why I used the capacity tests as the one I believe . A lot of guys take the 3 readings and average them. I think either way is ok as long as you explain how arrived at your numbers . Thoughts ?

  2. #2
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    3,554
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    I check flow by measuring pressure differential using 1 (one) known good gauge, and moving it from entering water to leaving water. Compare the differential with the manufacturers specs. Be aware that this works only if heat exchangers are clean and no other devices (such as strainers, throttling valves, etc.) are between the gauge taps.

    I also verify the installed temperature sensors with a known good thermometer.
    In honor of RichardL: "Ain't 'None' of us as smart as 'All' of us".

  3. #3
    Join Date
    Aug 2019
    Location
    Central Florida
    Posts
    106
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    Thread Starter
    The great ( or bad ) thing about T&B is there is more than 1 way to get it done . I always try to make sure all the temperatures are correct . The pressure drop can tell you that you think you have design flow at a cooling coil . However , if the leaving temp is 59 degrees I would surely open it up to obtain somewhere closer to design leaving temp . Do you guys calculate the total cooling / heating capacity of air handlers and such ? Just asking as I know a lot of union firms do not .

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