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  1. #14
    Join Date
    Jan 2004
    Location
    Earth
    Posts
    4,879
    Rarely have I seen an anemometer/velometer come out of the truck, there are times when you do need to dust it off and get it though. Generally there are other indicators of flow issues, and my fingers have been calibrated.

    Gas n Go, when the EPA finds a way to make markets pay to have it done that way, we will do it. Until then, we live in the real world.
    A Diamond is just a piece of coal, that made good under pressure!

  2. #15
    Join Date
    Jun 2001
    Location
    Michigan
    Posts
    12,077
    Yeagh well solid. You sound like one of dem old timers.

    I like my smoke. But I know many guys who can walk a line and give you digital accuracy with the back of their hand.

  3. #16
    Join Date
    Jan 2004
    Location
    Earth
    Posts
    4,879
    It's not about how you do it. It's about getting it done.
    A Diamond is just a piece of coal, that made good under pressure!

  4. #17
    Join Date
    Jun 2004
    Location
    Eugene, Oregon
    Posts
    1,018
    Originally posted by Dowadudda
    The damn DA sensor was off. I get my good digital out and we find that someone had put a offset in. Remove the offset and she was all good.


    What is a DA sensor?
    "The bitterness of poor quality remains long after the sweetness of low price is forgotten". --Benjamin Franklin
    "Don't argue with an idiot, they will drag you down to their level and beat you with experience". --Mark Twain
    http://www.campbellmechanical.com

  5. #18
    Join Date
    Jun 2001
    Location
    Michigan
    Posts
    12,077
    Your name is Air1 and you don't know what a DA sensor is. Cmon. Either pick a new name or fill the shoes of that name.

    Just kidding brother.

    Dishcharge Air Sensor. We control case temps based off Disharge Air Setpoints using a disharge air Sensor. DA sensor.

  6. #19
    Join Date
    Jun 2004
    Location
    Eugene, Oregon
    Posts
    1,018
    Originally posted by Dowadudda
    Your name is Air1 and you don't know what a DA sensor is. Cmon. Either pick a new name or fill the shoes of that name.

    Just kidding brother.

    Dishcharge Air Sensor. We control case temps based off Disharge Air Setpoints using a disharge air Sensor. DA sensor.
    Im not a market tech so Im not familiar with your jargon. We usually call them discharge air sensors.
    "The bitterness of poor quality remains long after the sweetness of low price is forgotten". --Benjamin Franklin
    "Don't argue with an idiot, they will drag you down to their level and beat you with experience". --Mark Twain
    http://www.campbellmechanical.com

  7. #20
    Join Date
    Oct 2001
    Location
    Waterford Michigan
    Posts
    2,668
    I'm surprised you would even open a system while it's under a vacuum.

  8. #21
    Join Date
    Sep 2004
    Posts
    3,157
    went over and asked him had he smoked the honey combs yet. He had no clue what I was talking about.

    I know this is going to be a shock to this entire board
    but since I am a student that is not employed yet in this type of work, ill admit to this once and once only :

    i havnt a clue as to what your talking about either and I would really like to know

  9. #22
    Join Date
    Jun 2001
    Location
    Michigan
    Posts
    12,077
    CT2,

    when someone says smoke, in this arena anyway. It means simply did you check for airflow using a smoke stick. It can be a real pain to have to pull product out of the bottom of a fixture and take a physical look at the evaporator. A smoke stick is nothing more than a thing where you break it in half and if you blow air on it, it creates a white smoke. You use a respirator like the doctors use when checking your blood pressure. You spray the smoke in the air stream path, and it will show you how the air flow is traveling. Often, when you think you might have restricted airflow, due to the case seeming to be warm, you smoke it first and try to compare that air stream with that of a another case next to it. If they seem very similair, you know that the evap fans are working and that chances of ice build up restricting airflow are not happening. You can eliminate these two things from your diagnosis, with out pulling product, and with relative quickness.

    Some guys claim they have a feel for the air flow using the back of their hand. And some guys are good at it that way. But I also have seen guys miss a iced up coil, some of the best and wisest. So personally, I always want to back up the back of my hand method. And it's so easy.

    Other, more accurate ways, is to use a mini velometer. Mini, due to it's size and the size of most honeycombs, and velometer because it measures aif flow. Accurate, yes. But very often you do not have the correct precise air flow data for that case your working on right then and there. Chances are if the section of cases or cases has worked in the past for years and now you all of a sudden have a problem with temperarture, it's not going to be for example, all the wrong kinds of fans are now in the thing, although sometimes you can't rule that out.

    Using smoke is just a simple method to determine quickly if you have air flow or not, it is not a precise measurment of airflow like the velometer. It's great quick way. Sometimes, you'll not be able to tell with out the help of a smoke stick, and you don't want to needlessly have a case pulled of product until your absolutely sure you need to dig into the case.

    The HONEYCOMB, is the section of the case, normally on top, pointing downwards, in front, where the refrigerated air comes out, then shoots down over the front open section to be drawn into the return air inlet. It's so named because they look like Honeycombs that bees make.

    Most of your refrigerated fixtures in a store, are very simialir in style and function. You can see by my decsription how, the way the air flow travels, is that an air curtain is made. An invsible one. Behind that invisible air curtain is your product being refrigerated. The HONEYCOMB style of air register if you will, is used instead of just any plain old thing is because it can creat steady, straight, streams of air in a solid path to the return air. In some instances, normally that of Multideck frozen food fixtures, you will see up to three different honeycomb sections, representing 3 different air streams. The nearest one to product would be your primary for refrigeration, your secondary to refrigeration, and the 3rd being what we call an ambient layer. That ambient layer is where, so you do not have store ambient air, being forced into the case. It's a protection air curtain. If store air was being forced into a case, which is what most call "wash out", that smoke stick will identify that in no time, and I couldn't really tell you how you could determine it otherwise.

    Air flow in refrigerated cases can be very suttle. So you need to understand what it was designed to do, and then go from there, as there are many different manufacturers.

    Lastly, and sorry for going so long, just because you might encounter a setup where by they run fans in eleectric defrost, or during hot or kool gas defrost, or where they terminate by DA air, or by coil temp or whatever combination of sequences you see happening. If you run across a system where it just aint working properly, like icing up and or whatever, what I call defrost problems, don't assume what your seeing is right. Always dig for the info to see how the case in question should be controlled per the manufacturer. By my own experience, I have fixed a lot of case not set up the way they were designed and after other technicians, or contractors for years were having problems with a certain fixture.

  10. #23
    Join Date
    Apr 2002
    Location
    Omaha, NE
    Posts
    1,561

    Dow, Thanks For Sharing That

    I always like to learn something new. That's what's great about this site.

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