Does a power supply blow air out or suck it in.

[Mucho]

?

 

[wisdomtooth]

Some older PSUs suck in... Made in the days when computers don't run hot.

The PSUs these days usually blow out to help vent a hot-running computer.

 

[KoolDrew]

Originally posted by: wisdomtooth
Some older PSUs suck in... Made in the days when computers don't run hot.

The PSUs these days usually blow out to help vent a hot-running computer.

 

[Navid]

Air enters a power supply from the case and leaves it from the back.

This is done differently.

In most power supplies a fan mounted on the side of the PSU and facing the back of the case blows air out the back out of the PSU. So, the fan blows air out the PSU and out the case.

In some power supplies, a fan is installed inside the PSU that is on the side that is inside the case. This fan sucks air inside the PSU from the case. As a result, the air pressure inside the PSU is higher than the air pressure outside the case. Because of this pressure difference, air is pushed out the PSU and the case from the side that faces the back of the case. So, the fan sucks air into the PSU but pushes air out the case.

Some PSUs have both of these fans.

Either way, air enters the PSU from the case and leaves the PSU out the back.

Under no circumstance should air exit the PSU into the case!

 

[wseyller]

I believe in the older AT form factor they used to suck in air, but it was realized that it wasn't a good method so it was changed.

 

[jackschmittusa]

Wow! A Dell that sucks. lol

 

[wisdomtooth]

Yep, under the original ATX 1.0 specification dreamed up by Intel back in the '90's, it called for a PSU to blow air INTO the case with a side-mounted fan at a CPU heatsink to help cool it.

I had an Enlight PSU from way back when that does exactly this. This was supposed to work with the then-new Klamath Pentium-2s with its heat-trapping SECC1 cartridge. Those Intel engineers must be high on crack back during those days.

ATX 1.1 spec changed it to a PSU that blows out-- Good riddance.

 

[mshan]

There are user forums at Dell's website where you can search the archives or post a question about your specific model and see if the fan was put in correctly:

http://forums.us.dell.com/supportforums/

 

[Mucho]

Thanks for the reply guys.