Fan direction

Gegerty

Is there a right and a wrong way to install a fan? Presumably the air is sucked in one side and blown out the other side. How do i know which way around to put it? Putting my hand over the fan while its on doesn't really tell.

Also, should the case fan which sits next to the CPU fan be blowing air onto the CPU fan or sucking air away from it?

btw, the fans I'm using are "Sharkoon SL3 ultra silent" fans.

Cheers.

Endurance Man

If you look along the outer rim of the fan there should be 2 little arrows which indicate which way the air is flowing. Another way would be to switch the fan on and note which way the blades spin .
The case fan above the cpu should be sucking air out of the case.

http://pictures.xbox-scene.com/3/80mm-fan/direction.jpg

Something like that.

L31mr0d

well plugging it in SHOULD tell you which way the air is blowing. Otherwise you've got a pretty weak CFM coming off that fan and its probably not worth your while. My fans don't have those arrows that Endurance man is talking about.

The way i tell is basically logic. Looking down at the fan blades, if the blades are concave (i.e. curved in) then its going to blow air towards you. If they are convex (do i have to say, curved out) then it is blowing air away from you.

Usually you want some fans sucking air in, and some sucking air out. Where you should place these fans, and at what orientation is up to debate. But the fan at the back of your computer sucks air out, the CPU fan blows air onto the heatsink. I have a fan at the front of my computer sucking air in, but you might consider placing a fan above your CPU to suck air in to help cool it. Also, a common hotspot is in front of the PSU, you might place a fan in the top of your case there, sucking air out.

Or go with W/C and forget fans

Gegerty

Cheers guys. I don't have the arrows but the concave/convex makes sense.

KdjaCL

Drop a small piece of paper in front of it should tell you which way the wind is blowing

I have 4 case fans one at the front sucking one at the side sucking and the 2 at the back blowing out.

Keeps it nice and cool.


kdjac

Gegerty

Now I'm confused. I have a sharkoon cus2 cpu fan and heatsink. The fan came attached to the heatsink so its safe to say it is the right way around. Thing is, the convex curves are facing up. Holding my hand over it there is a definite blow outwards but I suppose that is the air bouncing back out off the heatsink? So am I safe to say the convex curves facing me means the air is blowing away from me? Or is it different for different fans?

I'll try the paper trick.

Gegerty

scrap what I just said I've just confirmed what L31 was saying : ) I think I better leave it until the morning before I melt my computer!

conzy

You cant tell what way its moving air just be looking at the shape of the fins, you have to see what way it is rotating also.

And if the fan is so weak that you cant feel which way air is moving, it wont help cooling at all.

Gegerty

I can't feel which way the air is blowing because its already mounted and is beside the cpu fan and when i put my had near it theres just air flow all around it. Its a load of hassle unmounting it (its wedged in place pretty good) so i thought I'd ask on here instead to save me the hassle. Anyways I ended up unmounting it to get a better feel and its as mentioned above. I'd imagine there is an industry standard for the direction of the fan. I find it hard to be believe they just assume everyone understands the physics of it. Or then again I suppose they just expect people to check the direction before they mount it!

implosive

Wow Wow Wow, your meant to have one blowing in and one blowing out ! O crap i hav got both mine sucking air in ! What wil happen if i dont change it ?

conzy

The world will end:p

Just change one, have the one closest the CPU pulling air in and the other pushing it out

implosive

Heres how it is now !
View
Will the air not get sucked tru the psu fan ?

L31mr0d

Dont have your fan at the back of the case sucking air in. Make that one the exhaust and have the one at the front sucking air in.

Think about it, your psu is sucking hot air out, and your back fan is sucking this hot air back in again, along with pushing the hot air from the cpu all around your case, you want to get the hot air around your CPU out of your case asap. Plus usually the air at the front of your case is going to be cooler, so it should be sucked in.

DemonOfTheFall

Having the fan near your cpu blowing in will kill airflow to your graphics card. Been there and tried it.

Just follow the ATX spec with fan at the bottom front pulling in and fan at the back pushing out. Works best usually.