Positive Airflow

Donny84

Donny84

Donny84

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Joined
6 Mar 2013
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286
Hi guys, not sure if this is the right forum section but here goes...

I've been looking at the best setup for my fans in my case and I've read that a positive airflow is best to keep out dust etc.

My current setup is:
Corsair 450D case
2x 140mm fans at front - intake
2x 140mm fans on radiator at top - exaust
1x 120mm fan at rear - exaust
All fans are corsair.

At the moment I guess I have a negative airflow, which is sucking in more dust from holes, etc in the case.
I have space for 2x 120mm fans at the bottom, but since my case is on the floor and moving/raising my pc is not an option, I'm guessing it will suck dust in from the floor.

Any ideas?
 
Unless bottom fan positions have filters, fans in there would definitely just suck more dust into case.
And floor level tends to be very good place to find dust.

But radiators tend to have notable airflow impedance, so overall airflow balance might actually be rather even.
Running front intake fans at slightly higher speed and rear fan at slower could help to make it positive pressure.
With good fan controller that would be trivial thing to do.
 
orbitalwalsh said:
^^^

just swap the rear for intake and stick a filter on it :D
Click to expand...

Yep, I have a similar fan config. Two 120mm at the front, one 120mm at the rear, all filtered and a top 180mm exhaust. Difference is I have another 120mm PWM exhaust on the rear that kicks in only when it's hot enough, that drags heat straight off my CPU and GPU and probably does result in negative pressure when it's on full. The rest of the time, not really.
 
Fans blowing against each other is going to make a right mess of the air inside. You'll have warm air cycling all around.

Presumably you have filters on the front, so they'll be impeded just as those on the top by the radiator.

The easiest way to test would simply be to take a incense stick, or blown out match, and put it near any open grills that don't have fans on. Or PCI slots at the bottom. If the smoke goes in, you've got negative air pressure, out, and you have positive.
 
i use the, does the small piece of tissue stick to the grill/pci slots or fall down case pressure test.
 
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