Psu fan upgrade/orientation

CONSOLE_BUTCHER · 7 May 2017 at 21:58

Basically my psu is upside down so now the fan is in push mode. Would it be worth it to flip the fan so its pulling ? Also what about buying a new fan to put in it.

hornetstinger · 7 May 2017 at 22:00

Don't open the PSU.

RJC · 7 May 2017 at 22:09

If your PSU can pull cool air from under the case then I would personally leave as is.

pastymuncher · 8 May 2017 at 09:38

The idea of the psu fan pushing (intake for the psu casing) is that it forces air over the heatsinks and other components. If you turn it around you won't get the same level of cooling and could possibly increase the chances of psu failure. Manufacturers have them that way around for a reason plus they know what they are doing so leave it alone.

deFiniLoGy · 12 May 2017 at 03:47

According to a Seasonic Rep from a separate forum, if you're using Hybrid mode (i.e. semi-fanless) it's actually recommended to have the grill facing upward to let the positive pressure inside the case push air through the PSU, whereas if you're using active mode (i.e. fan always on) or if the case has a enclosed bottom basement then it's better to have the grill facing downwards so that it can pull fresh air to actively cool itself.

pastymuncher · 12 May 2017 at 09:11

That makes a lot of sense. I think he was on about flipping the fan inside the psu though, not the psu itself.

Sasahara · 19 May 2017 at 00:06

deFiniLoGy said:
According to a Seasonic Rep from a separate forum, if you're using Hybrid mode (i.e. semi-fanless) it's actually recommended to have the grill facing upward to let the positive pressure inside the case push air through the PSU, whereas if you're using active mode (i.e. fan always on) or if the case has a enclosed bottom basement then it's better to have the grill facing downwards so that it can pull fresh air to actively cool itself.

From that I can tell the seasonic rep, has limited knowledge on air pressure. If there was enough air pressure to counter thermal dynamics (unlikely) it would work just as well if not better with the fan face down, as long as there is an air intake within the case as it would be working with thermal dynamics, not against it. This is basic secondary school level science. :/

A fanless/hybrid PSU is designed to run at the heat the PSU produces and with the fan face down and no vent on the top, any heat that is produced with rise up and then out the rear. This process will create it's own air current without a fan.

This topic is a pet peeve for me. >_< If I can be arsed at some point I may produce a diagram to show this more clearly, cause it seems people need to be educated.

deFiniLoGy · 19 May 2017 at 00:32

Sasahara said:
From that I can tell the seasonic rep, has limited knowledge on air pressure. If there was enough air pressure to counter thermal dynamics (unlikely) it would work just as well if not better with the fan face down, as long as there is an air intake within the case as it would be working with thermal dynamics, not against it. This is basic secondary school level science. :/

A fanless/hybrid PSU is designed to run at the heat the PSU produces and with the fan face down and no vent on the top, any heat that is produced with rise up and then out the rear. This process will create it's own air current without a fan.

This topic is a pet peeve for me. >_< If I can be arsed at some point I may produce a diagram to show this more clearly, cause it seems people need to be educated.

Not entirely scientific but it does demonstrate that it's more situational than secondary school level scientific theory.

Also, per your description of the micro-climate of the PSU, if the fan is facing downwards, assuming there is no external heat source, has a more resistance to the air current than when with the fan facing upward since as hot air raises, a close air vent in the path of the raising air will produce resistance compared to an open air vent.

EsaT · 19 May 2017 at 15:57

If needing to ask which way PSUs fan blows air it's best to keep fingers far from PSU's insides.

Sasahara said:
A fanless/hybrid PSU is designed to run at the heat the PSU produces and with the fan face down and no vent on the top, any heat that is produced with rise up and then out the rear. This process will create it's own air current without a fan.

Convective temperature difference based cooling works best with as little as possible obstacles in path of warm air.
And air having to squeeze through between PSUs components and then rear mesh is definitely more restrictive than warm air being able to rise straight up.
Components farthest from rear mesh might have problems in getting airflow.

Again with fan running and forced airflow there just shouldn't be any significant differences for as long as there's no restrictions for fan's intake airflow.
Though with PSU on bottom having fan upwards is risk of screw falling into PSU.
Even if there's no power and it doesn't cause short circuit that screw might not come out so easily.

Doogles · 19 May 2017 at 22:06

I always have mine facing down for dust reasons, the bottom has dust filters but the top of my case doesn't which some dust gets through even with my magnetic modded filters covering it.