# determining air flow direction of a fan..



## jach11

usually the sticker side means exhaust. Take a paper and see which side sucks the paper in rather than push it out.


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## Faraz

The absolutely sure-fire way without turning on the fan is to judge based on concavity and convexity.

The concave side will exhaust. The convex side will intake.


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## LiFTed

I hope this makes sense:

The side of the fan on which the middle/round part that houses the motor, if that side is facing toward you, then the air will be blown away from you. The side that doesn't have the motor cover is the side that it will push the air out.


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## clark_b

Quote:


> Originally Posted by *jach11;12523490*
> usually the sticker side means exhaust.


^this

never encountered a fan where this wasn't true

:edit:
sticker side is the one with the "struts" going to the center of the fan


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## Scorpii

Most fans I've come across have two arrows on the side, one indicating rotation direction, the other indicating air exhaust direction.

Failing this, you could just plug it in and turn it on, the side you feel air being pushed on is the exhaust side...

Or sometimes the sticker on the hub is on the exhaust side.

Or, as faraz said above, concave = exhaust side


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## MIKEVALL

Usually there is a small arrow. blades are a tell tail sign.


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## Kick

the side with the 4 supporting things that come out from the middle is the exhaust.

ex:










you see the 4 supporting things that come out? that's the side that air blows to ( exhaust )










the side that doesn't have the 4 support things = intake like the above image shows


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## cuad

trial and error.


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## Mongol

sticker side...almost always exhaust.

the side that has no struts/grill protecting the fan blades is usually intake.


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## Dom_sufc

Plug it in if you're still unsure.


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## Wiremaster

Quote:


> Originally Posted by *faraz1729;12523497*
> The absolutely sure-fire way without turning on the fan is to judge based on concavity and convexity.
> 
> The concave side will exhaust. The convex side will intake.


This is correct. I've had fans with stickers on both sides.


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## Wr3ckin_Cr3w

Quote:


> Originally Posted by *Kick;12523561*
> the side with the 4 supporting things that come out from the middle is the exhaust.
> 
> ex:
> 
> 
> 
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> 
> you see the 4 supporting things that come out? that's the side that air blows to ( exhaust )
> 
> 
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> 
> the side that doesn't have the 4 support things = intake like the above image shows


+1

This is how I've always determined the exhaust


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## JAM3S121

Quote:


> Originally Posted by *Kick;12523561*
> the side with the 4 supporting things that come out from the middle is the exhaust.
> 
> ex:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> you see the 4 supporting things that come out? that's the side that air blows to ( exhaust )
> 
> 
> 
> 
> 
> 
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> 
> 
> the side that doesn't have the 4 support things = intake like the above image shows


thanks i appreciate it!


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## Kick

np man. gone through my share of fans and used that technique and hasnt failed me yet.


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## imadude10

That or, all the fans I have ever owned have arrows on the side. One shows airflow direction and the other shows direction of blade rotation.


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## Kick

Quote:


> Originally Posted by *imadude10;12523798*
> That or, all the fans I have ever owned have arrows on the side. One shows airflow direction and the other shows direction of blade rotation.


yeah but OP specifically stated there was no markings...


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## ehume

Unless it's an Arctic Cooling cage fan, the air goes over the struts.


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## Bing

Quote:


> Originally Posted by **********;12523584*
> sticker side...almost always exhaust.
> 
> the side that has no struts/grill protecting the fan blades is usually intake.


The unusual exhaust orientation.


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## ehume

Forgot about Papst. Some of theirs turn clockwise, too.


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## Crazy9000

Quote:


> Originally Posted by *ehume;12527923*
> Forgot about Papst. Some of theirs turn clockwise, too.


Must be Australian.


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## Bing

Quote:


> Originally Posted by *Crazy9000;12527952*
> Must be Australian.


Naah.. its German.


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## clark_b

Quote:


> Originally Posted by *Crazy9000;12527952*
> Must be Australian.


lol i'm assuming this is a reference to the toilet flushing thing right?


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## ShortySmalls

the side that has the 'bar' on it is the exhaust side, but their has always been a little arrow on the side of the fan somewhere engraved into the casing.


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## mtbiker033

sticker is exhaust side as mentioned above


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## pyro_dude

Quote:


> Originally Posted by *Crazy9000;12527952*
> Must be Australian.


Actually papst fans are german made. They are really good fans tho!


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## ehume

Quote:


> Originally Posted by *pyro_dude;12549897*
> Actually papst fans are german made. They are really good fans tho!


Good and loud. And clicky. I did have an EBM fan (merged with Papst) that was all steel - frame, struts, blades, hub. Bet that'll still be working when we've all passed from this mortal coil.


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## homestyle

yeah sticker side... aka... the side with the wires coming from the center out.


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## Chuckclc

WTH! There are markings showing the airflow. I never saw this before, but its probably cuz I never looked hard enough. Anyways, I always went with the side were the blades were easily accessible was the pull and the side with the slight guard was the blowing side.


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## iatacs19

Quote:


> Originally Posted by *faraz1729;12523497*
> The absolutely sure-fire way without turning on the fan is to judge based on concavity and convexity.
> 
> The concave side will exhaust. The convex side will intake.


This is the surest way. It's just fluid mechanics.


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## singerplayer

usually the sticker side means exhaust.


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