X-flow radiator, inlet on bottom or top?

BinarySynapse

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Feb 6, 2006
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My thoughts (which are probably wrong) are that since air rises, having the outlet at the top means more air can potentially keep circulating through the the rest of the loop. Having the inlet at the top means that any air that is in the loop would more likely get trapped in the top of the radiator and not continue circulating through the loop.

As for gravity helping the pump: however far the water falls, it’ll have to be lifted back up that same distance to get back to the pump. So there’s no benefit one way or the other.
 
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I honestly don't think it matters. Air may get trapped in the endtank on top, but that won't impact anything. Over time that bubble will eventually get worked back through the loop and get trapped in the res where it belongs.
 

Digital Viper-X-

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Thanks for the replies, as you can see VanGoghComplex your Rad is finally being put to use :).

I just wanted to avoid noise, and read somewhere that upright U-flow rads can get noisy due to air stuck on top.
 

Tsumi

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I doubt it matters, and you're going to want to get as much air out as you can anyways. I would route it in a way that uses the shortest lines possible.
 
Joined
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Thanks for the replies, as you can see VanGoghComplex your Rad is finally being put to use :).

I just wanted to avoid noise, and read somewhere that upright U-flow rads can get noisy due to air stuck on top.
I had that rad mounted with the top as the inlet and never had any kind of gurgle problem, but I don't think I would have had one of the rad were flipped. I think trapped air is far more a 'low flow' problem than it is a component orientation problem.
 
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