Relative height of components

B

Bluedragon9r

n00b
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Nov 11, 2004
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To the best of my knowledge, you want to have a reservoir at the highest point in the system. That would provide maximum NPSH to the pump, and also ensure that any air in the water will eventually work it's way to the reservoir. I know this is true for much larger cooling systems (which I know from my work). The question is, how much does it matter in a PC cooling system?

The reason I ask is that I'm working on back fitting some higher end watercooling components into a case that had a built-in system. The 2x120 rad will go in the top of a Lian Li V1200 case, and the reservoir will be a couple inches below it in the 5 1/4 drive bay cage, then the pump will be mounted to the bottom of the 5 1/4 cage.

Do I really need to worry about air getting trapped in the radiator with this setup? Or should it be OK once it's bled?
 
It doesn't matter at all, in a closed loop system of this size. Since rise will always equal fall, the net effect of this is 0.
 
yep once you bleed it or use another method to expel the air bubbles= no worries.
 
yep yep, only thing is that in general it is better to have the res above the pump and directly feeding into the pump's intake to eliminate any possibility of running the pump dry. If this presents a mounting/routing problem its not critical but in general rez right before pump and higher (even just a little) is preferred.

Its a real kick to take the top off the rez when it is mounted low in the case and figure out why the water does not come out ;)
 
Thanks for the info..When you're talking 20-30ft between the tank and the pump, it's a huge difference. I was still thinking along those lines for the case. When you think about it though, the 5-10" difference in height isn't going to add a noticeable amount of pressure to the pump inlet. I need to scale my thinking down a little bit!
 
What I alluded/hinted too above is that is a loop, the column of water at the pumps intake is balanced by the column of water at its outlet so the net pressure (head) is 0, it will not mater to the pump where it is in the loop.
 
Correct for a sealed or pressurized system. Good ol' Bernoulli's equation.

The only difference would be for a vented system, if you opened the tank when it was running to add more coolant for example.
 
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