Fan Exhausts up instead of down

Perryg114

Senior member
Jan 22, 2001
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So what is up with the new power supplies having the fan exhaust up so on some cases the fan is blocked by the top of the case. I seem to remember that the older power supplies had symetrical bolt patterns so you could mount them with the fan up or down.

This is right up there with them taking the PS2 mouse ports off of motherboards. I have noticed that they put them back on the newer motherboards.

Perry
 

theAnimal

Diamond Member
Mar 18, 2003
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The only exhaust fan on a PSU would be found at the back. AFAIK the intake fan is still on the bottom of the PSU. You can however mount them upside down if you wish.
 

Perryg114

Senior member
Jan 22, 2001
768
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The inside fan is on the wrong side. It is up against a plate where no air can flow. Direction is not an issue. If there is a plate there it won't matter which way the fan is blowing.

Perry
 

Zepper

Elite Member
May 1, 2001
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Well, some cases have screwed up PSU mountings, so if your case can only mount the PSU so it puts the fan upward, then if you have at least an inch or so of space there, you'll be OK. If not, then you'll want an old-school PSU like most Antec EarthWatts models that run the air straight thru. Or dump your case and get one with a more current (or bidirectional) PSU mounting. Actually, I like PSU mountings that put the main PCB in the PSU on the bottom, but if there is no room for the fan to breathe, then something will need to be done.

Most modern PSU fans aren't designed to contribute to overall case cooling (back in the day, the PSU fan might be the only one in the case), so they generally don't flow much air any more - just enough to cool the PSU.

.bh.
 

Aluvus

Platinum Member
Apr 27, 2006
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Power supplies with large fans are usually photographed upside down. The fan is on the bottom, once the supply is mounted in a typical ATX case. The fan is an intake, drawing air into the supply, and not an exhaust.
 

Zepper

Elite Member
May 1, 2001
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Yes, the one large fan on the side is the only fan and it does blow into the PSU - the exhaust is passive as the air just leaves thru any available venting, but mostly at the rear. Some sleeve bearing fans in PSUs like the Enermax Liberty that I had here, complain noisily when in other orientations than standard (meaning fan on the bottom). Ball bearing fans shouldn't mind working in either direction.

.bh.
 

Perryg114

Senior member
Jan 22, 2001
768
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Yes my cases were designed for the old flow through power supplies but if the newer style power supply had the fan on the opposite side it would fit ALL the cases and it would also improve air flow off of the CPU, since it would suck in the air coming off the bottom of the CPU heat sink and then blow it through the power supply. Yeah it is a few degrees hotter than the ambient air but not by much. I can drill holes in my case so I can mount the power supply with the fan down but it seems not much thought goes into these things.

Perry
 

Zepper

Elite Member
May 1, 2001
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Most recently designed or updated cases have proper PSU mountings for the large fan PSUs, or a rotatable mount plate so the fan can be oriented downwards or upwards at your preference (I'd prefer upwards if there was room and the fan itself didn't protest). Or they have extra mount holes, so either way will be accommodated. They just won't let you hold on to old gear any more... The PSU makers would have had to do a complete mechanical redesign on the PSU chassis to put the fan on the bottom while the mounting holes remained in the old standard locations. Instead, they decided to force the case makers to do the changes to accommodate them. That's just the way it is. Old case out - new case in.
. Most old-school PSUs also had asymmetrical mount holes so the PSU could only be mounted the correct (IMO) way - meaning with the main PCB on the bottom side. I still consider it the correct way as better support is given to the components and heat rises up away from the PCB and components instead of being trapped under the PCB... I received several EA PSUs with broken leads on coils at least partly because they were shipped with the PCB on top instead of bottom, but mostly because no coil supports were used to take the stress off the coil leads.

.bh.
 

Perryg114

Senior member
Jan 22, 2001
768
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Well I have some of the newer cases but for my secondary computers I just use the cases I have had for several years. I supposed when the motherboard form factor changes I will be SOL and I can recycle them. I can drill a few holes.

Perry
 

Zepper

Elite Member
May 1, 2001
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I can't see them needing to change the standard mobo mount locations - the boards may shrink or expand a bit, but the hole spacings will remain the same for a loooong time.

.bh.