Which side of a case fan is up?

[DBMaster]

I have a couple of Logisys 120mm clear case fans. I am trying to
determine which side is "up", so to speak. On black case
fans there are arror markers to tell you which direction the fan
turns and the direction of the airflow. There is no morkings on the
clear fans. Am I just missing the obvious and I should just connect
them and feel which way the wind blows? I must caution that I did
try that and the temp inside the computer got up to 159F before there
was a flash nd a bang and the power supply blew. Luckily the
motherboard seems to be OK. I built the computer myself (it is the
10th one , I think) ,but this is the first time I built one for
myself. I built or modified computers for family and friends, but I
was building my ultimate computer, with the clear view side, cool
(literally) lights and as many fans as I could reasonably cram into
the case. Some of the fans were the lighted kind Hey, I should be
able to have a little bling bling in my computer if I want. Anyway, I
learned about positive case pressure and stuff like that after the
blow up. What I need to know is how to determine which side of the
fand to use.
Any help would be most appreciated !

 

[kony]

I have a couple of Logisys 120mm clear case fans. I am trying to
determine which side is "up", so to speak.

There is no "up" really, just intake or exhaust.
On most any typical fan the center support struts are on the
side air exhausts from. The curvature of the fan blades
will be concave on the exhaust side too. Rarely some
proprietary fans are reverse of this, suspended designs such
as Intel uses on their retail CPU bundled 'sinks or some
other 3rd party products but usually this is not the case.

On black case
fans there are arror markers to tell you which direction the fan
turns and the direction of the airflow. There is no morkings on the
clear fans. Am I just missing the obvious and I should just connect
them and feel which way the wind blows?

You could of course, but it's highly likely they are as
described above.

I must caution that I did
try that and the temp inside the computer got up to 159F before there
was a flash nd a bang and the power supply blew.

Where did you put the fan? It will make a difference which
way the fan blows but it shouldn't be THAT much of a
difference. It should not blow the power supply, if
anything pointing the fan the wrong way would tend to help
the power supply remain cool by reducing impedance
(pressure) to it's integral fans. It shouldn't be a goal
though, if that difference is significant it can be a sign
the system case had insufficient front intake area.

I'd wonder if the fan were defective, or the wiring shorted
somehow, or some other variable not relevant to which way
the fan had been pointed.

Luckily the
motherboard seems to be OK. I built the computer myself (it is the
10th one , I think) ,but this is the first time I built one for
myself. I built or modified computers for family and friends, but I
was building my ultimate computer, with the clear view side, cool
(literally) lights and as many fans as I could reasonably cram into
the case. Some of the fans were the lighted kind Hey, I should be
able to have a little bling bling in my computer if I want. Anyway, I
learned about positive case pressure and stuff like that after the
blow up. What I need to know is how to determine which side of the
fand to use.
Any help would be most appreciated !

A rear case fan should exhaust out of the case, and a front
case fan should blow into the case. Especially considering
that your fan is 120mm, it is almost certainly going to
exhaust out the side with the struts holding the center hub.

 

[Timothy Daniels]

I have a couple of Logisys 120mm clear case fans. I am trying to
determine which side is "up", so to speak.

The side with the stick-on label and the exposed wires
is the exhaust side of the fan.

*TimDaniles*