PC Desktop Power Units

[redman41]

This is just an Observation and slight Criticism !!

My Packard Bell PC is under 4 yrs old and had Power Unit replaced on Sat.
The Cooling Fan on the New Unit is flush with the outer casing, whereas the Old Unit had a Fan on underside and out of sight inside the Tower, and in effect was 'cooling' the Unit with warm air.
Not a very well thought out design on Old Unit in my opinion and it probably contributed to the Units early failure.

[ChuckFickens]

It doesn't matter where the fan is, it's doing the same job because the PSU is effectively a sealed unit.

With the fan on the back it will be sucking in air from outside the case and blowing it out the bottom or front of the PSU into the computer case.

With the fan on the bottom it is blowing air out of the bottom of the PSU into the computer case, but that air is still being sucked in from the back of the machine.

It's pretty much like just having a fan right at the end of a tube or having one in the middle of a tube, the air will still come from the same place and go to the same place regardless of the position of the fan.

[ChuckFickens]

Though you can probably reverse the directions in my answer above, as most computers blow out the back, not suck in through the back.

But the principle is still the same, the airflow is a complete path right through the machine and the exact location of the fan on that path is irrelevant.

[redman41]

That is the way it is with the new one Chuck ! The old unit had the Fan on the underside of PSU and was sucking air from inside the Tower ! Not a good design in my opinion ! the new one sucks cool air from outside Tower.

[ChuckFickens]

If you are saying the direction of the fan (and therefore airflow) in the PSU has changed then you find you get overheating problems if there are any other case fans in the machine because they will now be running in the opposite direction to the PSU fan, meaning you'll now have two (or more) fans blowing air into the computer and none sucking the warm air out.

The cooling on a well designed case works with more than one fan and they all have to work together, so one will be sucking cool air into the machine at one end and the other will be blowing the warmed air out the other end. reversing the direction of just one of the fans stops the airflow going through the computer in the designed way.

On the plus side, having two fans sucking air into the computer will cause positive pressure inside the case and should stop it getting soo dusty inside :)

[redman41]

''On the plus side, having two fans sucking air into the computer will cause positive pressure inside the case and should stop it getting soo dusty inside :) ''

Agreed Chuck !! ha ha

[rojash]

"On the plus side, having two fans sucking air into the computer will cause positive pressure inside the case and should stop it getting soo dusty inside :) "

Of course you could re-phrase that:
"On the down side, having two fans sucking dust into the computer will cause a positively huge amount of dust to collect in it".

[James-Foster]

You need airflow for best cooling, as you are trying to transfer the warm air from the components to the air outside of the case. You can have additional flow paths from multiple fans pulling/blowing air in to multiples blowing/sucking air out, but you need a flow where the cool air from outside the case moves over the components such as your CPU, GPU and RAM before leaving the case.

[puternut]

There is also the 'problem' of airflow around the case. If the fan was underneath and the unit was on a deep pile carpet it wouldnt matter if the fan was blowing in or out. There would simply be little or no circulation.

As a warning to all : ensure the inside of your unit is de-duted at least yearly. I didnt do this. Video card got overheated and blew completely with sickening smell of burning.

[puternut]

^^ de-dusted