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Case Fan help: I want positive pressure, but how?

Discussion in 'General Hardware' started by Ghostsniper64, Oct 15, 2015.

  1. Ghostsniper64

    Ghostsniper64 Active Member

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    So as the title suggests, my case currently has negative pressure within the case so it's pulling in dust at a not-so-awesome rate. While the standard answer is "add more intake fans", I'd like the best way to do that without messing with the airflow direction of my case.

    I'm currently using a Corsair Carbide Series Air 540 with the default setup of included case fans, which are 2x 140mm intake and 1x 140mm exhaust.
    http://www.newegg.com/Product/Product.aspx?Item=N82E16811139022

    I can fit either 2x 140mm or 3x 120mm in the front, 2x 140mm or 2x 120mm up top, and 1x 140mm or 1x120mm in the back.

    My question to you guys is this: should I replace the two front 140mm fans for three 120mm fans, or just add intake or exhaust fans to the top of my case?
     
  2. fantaskarsef

    fantaskarsef Ancient Guru

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    Uhm... you already got positive preasure inside your case then if you've got two in and one out. You can always experiment with reducing your exhaust fan's rpm for instance, or increasing the front ones. Keep an eye on the temps though, can't hurt.

    I wouldn't put any intake fans on top of the case, it's against any natural air flow.

    If you want to have more airflow you can always put in more fans, but honestly I'm not sure it would help you much in an anyway dusty environment, where whatever you do, dust will make it's way into the case sooner or later (I know that situation :D)
     
  3. Greybeard

    Greybeard Active Member

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    I would say, 3 x 120 in the front and 2 x 140 on top at low rpm then a 120 in the rear. I would just keep the rear fan run on a lower rpm as well to maintain positive air flow inside your case. And fantaskarsef is correct not making your top fans intake, you'll probably get better results to have them on exhaust.
     
  4. thatguy91

    thatguy91 Ancient Guru

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    Hot air rises. Also, the CPU and RAM are located towards the top of the case. If you have the top fans on blow you're pushing the hot air back down over the rest of the motherboard and your GPU.
     

  5. Ghostsniper64

    Ghostsniper64 Active Member

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    I do not have positive pressure in my case, all of my vents are sucking in air (putting a piece of paper on them causes them to stick due to suction)
    Referring to adding more intake on top, yes, that would definitely mess up the airflow in my case. Should I just start covering open vents, (i.e. the empty fan slots up top)? While that may solve my pressure problem, as someone has already said, heat rises, and by blocking them off I'd probably be ruining my cooling capability of the system
     
  6. fantaskarsef

    fantaskarsef Ancient Guru

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    Well you have positive air preassure if everything is sucking in air... or better, the fans are pushing the air inside your case. I thought you had front on intake, back on exhaust, which would be the standard to set up a case I'd say. I'm also wondering what air flow you're talking about if everything is pushing in, and simply trying to find it's way out uncontrolled with every other opening than the fans...

    What I'd suggest you to do is: Close all the empty holes, and put the backwards fan on exhaust (pushing air outside of your case). That's what I personally would consider standard air flow model. Then you can add other fans, but all pushing in does not help your cooling too much I'd say.
     
  7. Tuoni

    Tuoni Member Guru

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    With all those fans all the air inside the case will be completely refreshed multiple times a minute. Natural convection of hot air in this situation is pretty much non existing. Hot air will go where you push it to with the fans.
     
  8. Extraordinary

    Extraordinary Ancient Guru

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    Yea you do have positive pressure, if all your fans are sucking air into the case...

    Think of it like blowing up a plastic bag, so long as more air is being forced into the bag, than is being sucked out, the bag will have a positive air pressure inside
     
  9. Deathchild

    Deathchild Ancient Guru

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    If you have dust, clean your room then.

    I have the same setup, 2 intake 1 ex, works fine for me. Although maybe adding a top back exhaust might be better as then the air would move a bit better and more.

    Though I think I'm fine on these temps, gpu reaches max 74-75c. Cpu is 60-70c.
     
  10. airbud7

    airbud7 Ancient Guru

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  11. Extraordinary

    Extraordinary Ancient Guru

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    Great example video ^^
     
  12. Ghostsniper64

    Ghostsniper64 Active Member

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    Let me rephrase my previous statement. I DO have 2 intake and 1 exhaust fan, but I have little grates on the back of my case (I called these vents, same thing) that allow air to pass freely. These are where the dust is coming into my case from. Also, the area where I can put two top case fans are also covered in mess, but that still allows air to pass freely. All of these open "grates" suck air and dust inside of the case. I can see that they're moving air inside of the case by placing a piece of paper near them to see which direction the air is flowing, and they pull the piece of paper toward the grates.

    And about cleaning my room, I do, and my computer has a dust filter over the front fans
     
    Last edited: Oct 16, 2015
  13. airbud7

    airbud7 Ancient Guru

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    off topic...> Hey Ghostsniper64 can you get me some Daytona 500 tickets? cheap :)
     
  14. Athlonite

    Athlonite Maha Guru

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    you fail basic theromdynamics there sunshine or is it not natural for hot air to rise.....

    now back on topic:

    I'd put that single 140mm fan from the rear up top and blank off any places you don't want air coming in and replace the two front 140mm fans with something that has higher CFM but still 140mm or 3 120 high CFM fans
     
    Last edited: Oct 20, 2015

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