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    propeller fan in relation (21 Posts)

  • paul paul @ 12:24 AM
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    propeller fan in relation

    what is the position of the propeller fan in relation to the venturi? or the height of the blade in the venturi opening?
  • Empire Empire @ 9:46 AM
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    ???

    I guess I'm not sure what you mean.  Do you have an example as in condenser fan, tower prop, etc...  Do you mean the shroud surrounding the prop?

    Peace;

    Mike T.
  • paul paul @ 11:38 AM
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    fan

    on a condenser fan shroud what is the height of the fan in the venturi . high low or in the middle. do i keep the blade even with the top of the shroud or below or what
  • Paul Fredricks Paul Fredricks @ 1:28 PM
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    .

    It would make sense that the middle of the shroud would be optimum. That said I don't think it makes that much difference. As long as the blade is within the shoud area it should be fine. As long as it's not so low that the air short circuits before it gets to the shroud.
  • Empire Empire @ 12:27 PM
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    Fan prop.

    I usually place it's position about 1 1/2" below the bottom of the shroud.  It will scoop the air and reject through the top.  If you go too much, increase in amp draw will result. 

    Mike T.
  • paul paul @ 2:17 PM
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    fan

    i have some older units and the venturi is shallow so i have been putting them at about in the middle . thanks for the info
  • EBEBRATT-Ed EBEBRATT-Ed @ 9:21 AM
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    Fan blade location

    Thats why it's best to mark them or take some measurements. I found out the hard way just like everyone else.
    If you can't find the location from the manufacturer I would suggest trying it in several locations to see where it moves the most air. Checking motor amps will probably be a good indicator
  • paul paul @ 6:54 PM
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    fan

    thanks for the input, will experiment and find a good sweet spot
  • Empire Empire @ 10:37 PM
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    Paul

    No diss, but your cracken me up with this "venturi" stuff.  What the hell are you trying to say????lol.   Been doing this for 28 yrs and dang, please up date me to the terminology.........Not a big deal, just thought you could clarify me on what you are looking at.

    MPT...
  • paul paul @ 5:08 PM
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    fan

    Empire, I am glad I crack you up. My brain don't work so good lately. Getting old and  can't remember simple things like shroud.  The units I work on the most are dry coolers with 4 to 5 fans on them. and after all these years of doing this I don't ever remember in the bookwork in school, or otherwise,  a fan position definitive answer. I may have been sick the day they talked about it , or maybe not paying attention. here are some photos of the units.
  • Dennis Dennis @ 10:48 PM
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    It is called a

    Volute
    Just do it, right.
  • Dennis Dennis @ 10:48 PM
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    It is called a

    Volute
    Just do it, right.
  • paul paul @ 1:19 PM
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    v word

    i knew it had a V word in it
  • Empire Empire @ 10:30 PM
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    Manfg. Spec's.

    If you can find them there spec's, I'll give ya a dollar.  Does not exist and especially for residential equipment.  Not sure what you men are calling "Venturi" or the like but Listen to what I stated nearlier and you will get what you are looking for.  The only concern I have is if there is actually a shroud or not..  Pretty easily set as far as prop position goes.  Actually not critical when you consider that an inch or 3 will not make a difference.  If shroud exists,...1.5 to 2.5 inches below shroud.  W/O shroud, as far up towards motor as possible.

    Mike T.
  • Techman Techman @ 12:36 AM
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    Fan height

    The easiest way is to be the 1st person to get his hands on this unit and measure/mark the height and start there.But,since your not the first you can get REAL close by putting the blade just about anywhere and then measure the motor amps (compare to nameplate amps) ,the subcooling and temp  of air across the cond coil vs.the saturated freon temp(typically 30* on a 95* day). And then move the blade up/down a little.Then I would look @ EVERY unit I walk past/ work on and see that there is no magic # across the board ,not that I have noticed anyway.
    This post was edited by an admin on September 4, 2012 1:41 AM.
  • Techman Techman @ 1:39 AM
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    Fan

    That 30* cond temp rise is for standard efficiency units ,25* for hi efficiency and 20* for ultra hi eff. units.
  • Techman Techman @ 8:17 AM
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    Fan height

    paul pic's help a little.The height of the fan guard helps a little,because the blade is usually/sometimes up higher inside the guard,but, nothing that is carved in stone.How about the motor nameplate amps vs. actual motor running amps?
  • Techman Techman @ 8:17 AM
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    Fan height

    This post was edited by an admin on September 17, 2012 8:21 AM.
  • Techman Techman @ 8:17 AM
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    Fan height

    paul pic's help a little.The height of the fan guard helps a little,because the blade is usually/sometimes up higher inside the guard,but, nothing that is carved in stone.How about the motor nameplate amps vs. actual motor running amps?
  • Techman Techman @ 8:18 AM
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    Fan height

    This post was edited by an admin on September 17, 2012 8:22 AM.
  • Techman Techman @ 8:18 AM
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    xtra

    This post was edited by an admin on September 17, 2012 8:20 AM.
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