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Thread: Testo 416

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  1. #1
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    Testo 416

    Has anyone tested the accuracy of the Testo 416 anemometer against a communicating controls CFM reading?
    I tested it against my Infinity control and am off by 200+CFM. Yes, I have traversed the return duct and taken 3 sample readings just like in these 2 videos.
    http://www.youtube.com/watch?v=dDVJE2rh9rM

    http://www.youtube.com/watch?v=YpBTlGLQ97A
    Any fool can know. The point is to understand. Albert Einstein

  2. #2
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    I have never used the testo, but my fieldpiece sta2 is always within 50 cfm of the blower setting. It is a hot wire, not a vane.

  3. #3
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    what reading was higher?

    sounds like some air leakage between the traverse and the blower, where the infinity calculated cfm vis rpm and torque
    my boss thinks its possible to repeal the laws of physics

  4. #4
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    Quote Originally Posted by ch4man View Post
    what reading was higher?

    sounds like some air leakage between the traverse and the blower, where the infinity calculated cfm vis rpm and torque
    The Testo read 1200's cfm and the infinity read 893 cfm

  5. #5
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    hmmm, dont know what to say to that.

    if two clocks disagree, at least one of them is wrong.........

    time to bring in a third way to measure your airflow ( and hope that agrees with one of your original readings)
    my boss thinks its possible to repeal the laws of physics

  6. #6
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    Ceurvo,
    Do you know the humidity and the temperature of the air that you were measuring? The Testo 416 measures airflow independent of the density. You ECM actually does not move a constant airflow but really moves a constant mass flow. If you have the air properties I can verify if the readings are the same.
    JLB,

  7. #7
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    Quote Originally Posted by jim bergmann View Post
    Ceurvo,
    Do you know the humidity and the temperature of the air that you were measuring? The Testo 416 measures airflow independent of the density. You ECM actually does not move a constant airflow but really moves a constant mass flow. If you have the air properties I can verify if the readings are the same.
    Interesting. Humidity 33% temp 79 wetbulb 61

  8. #8
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    CFM x density = LBS/Min

    Your air density is .0663 lbs/ft3 at 79/61

    Standard air = .075 lbs/ft3

    893 x .075 = 66.975 lbs/min

    1200 x .0663 = 79.56 lbs/min

    Something looks wrong with your air measurement. Is it possible that you entered the area incorrectly? Was the duct insulated? Did you take that in to account if so? Could you have been in a very turbulent spot?

    Considering the air density, corrected you should have read about 1010 cfm with the vane. That would be the equivalent of 893 CFM of standard air.
    JLB,

  9. #9
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    Quote Originally Posted by jim bergmann View Post
    CFM x density = LBS/Min

    Your air density is .0663 lbs/ft3 at 79/61

    Standard air = .075 lbs/ft3

    893 x .075 = 66.975 lbs/min

    1200 x .0663 = 79.56 lbs/min

    Something looks wrong with your air measurement. Is it possible that you entered the area incorrectly? Was the duct insulated? Did you take that in to account if so? Could you have been in a very turbulent spot?

    Considering the air density, corrected you should have read about 1010 cfm with the vane. That would be the equivalent of 893 CFM of standard air.
    I'll retest tomorrow at my own house and at a customers unit with and infinity control. Thanks for the info Jim!
    Any fool can know. The point is to understand. Albert Einstein

  10. #10
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    Shoot me a PM and I will give you some contact information if you need help tomorrow.
    JLB,

  11. #11
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    Quote Originally Posted by jim bergmann View Post
    CFM x density = LBS/Min

    Your air density is .0663 lbs/ft3 at 79/61

    Standard air = .075 lbs/ft3

    893 x .075 = 66.975 lbs/min

    1200 x .0663 = 79.56 lbs/min

    Something looks wrong with your air measurement. Is it possible that you entered the area incorrectly? Was the duct insulated? Did you take that in to account if so? Could you have been in a very turbulent spot?

    Considering the air density, corrected you should have read about 1010 cfm with the vane. That would be the equivalent of 893 CFM of standard air.
    Jim, that last sentence is confusing, i know pitot tubes and hot wires require air density corrections. im sure ive read that a mini vane does not. did you come up with 1010 cfm by correcting the 1200 the ECM read and assuming incorrect 416 readings?

    IOW both readings in this instance ( 1200 & 893 ) cant be trusted
    my boss thinks its possible to repeal the laws of physics

  12. #12
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    A typical fan moves a constant airflow independent of the air density. It is a constant airflow (CFM) and variable mass flow device.

    An ECM works on RPM and torque. The blower is profiled for standard air. They move a constant mass flow across the coil. As the air density decrease the amp draw on the motor goes down and so does the mass flow. The ECM speeds up to increase the torque and keep the mass flow across the coil the same. This is a big advantage as we are actually cooling the mass of the air.

    The vane measures airflow independent of the air density. What I simply did was convert all of the readings to mass flow instead of airflow then back calculated the CFM

    893/X = .0663/.075
    X = 1010
    JLB,

  13. #13
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    I think Jim joined an engineering book club, he's full of all sorts of data!

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