order of flow in loop?

jej_knowles

jej_knowles

jej_knowles

Associate
Joined
15 Nov 2008
Posts
485
Hi all ! I am about to install watercooling into my first ever self build.
I have a lian li pc-a71f case with a 360 rad top panel and will be modding the front intake fans to mount a 280 rad up front!
I have it all worked out in my head and have sketched loop flow diagrams and think i have decided on this.....
res/pump > 280rad > gpu > 360rad > cpu > res/pump

I have read quite a few threads saying that the order of flow makes no difference to the temperatures but i fail to see how that could be true as the water coming out of the rad has to be cooler than the water going in otherwise it wouldnt be working!

am i right?
 
jej_knowles said:
Hi all ! I am about to install watercooling into my first ever self build.
I have a lian li pc-a71f case with a 360 rad top panel and will be modding the front intake fans to mount a 280 rad up front!
I have it all worked out in my head and have sketched loop flow diagrams and think i have decided on this.....
res/pump > 280rad > gpu > 360rad > cpu > res/pump

I have read quite a few threads saying that the order of flow makes no difference to the temperatures but i fail to see how that could be true as the water coming out of the rad has to be cooler than the water going in otherwise it wouldnt be working!

am i right?
Click to expand...


Flow order doesn't make much difference at all. Obviously the first components in the loop will be cooler than the later ones, so put the components you want to be the coolest in your loop first.
 
My personal preference would be

res/pump > 360rad > cpu > 280rad > gpu > res/pump

There is a lot of conversation regarding the temperature in the loop evening out and there being no significance where the cpu/gpu are in respect to the rads.

The only thing you can do, is carry out a few tests and see what gives you the best possible results.
 
Order of flow does make a difference,but it's so tiny it's not worth concerning yourself with.

Start off with res/pump,as you've already supposed this makes filling and bleeding the loop a doddle.
Where you go from there is a case of whatever is simplest for you to route tubing/mount rads.

The water in your loop is going to reach equilibrium(i.e. the point where the temp is no longer going to rise) in around 30 mins of starting to load the loop,it's this final temp and the ambient temp you need to be keeping note of as a guide to how good your loop is at dumping the heat you need to dispose of.

This is called the delta or delta-t as some others prefer to call it.
Most modern watercooling enthusiasts try to build loops that run with a delta of around 10c above ambient,which is more important for cpu cooling than gpu.
If gpu cooling only a 15c is more than acceptable.

So all of this brings me back to loop order,from what you've described you aren't going sli/xfire so you dont have anything too restrictive.
If you did it would make sense to use a rad straight after a double+ gfx card setup,with a single card it's not important.
You also seem to know that a 280 and 360 rad is what you need in your loop to dump the heat generated by it (probably by a large margin).

With this setup I seriously doubt you'd be able to change equilibrium with noticable effect by using order of flow.

All this takes a lot of head scratching by anyone new to watercooling,but when the penny finaly drops it's a revelation.

I've tried to explain it all in very basic terms for a novice to understand and I really hope it helps,welcome to the joy of watercooling ;)
 
Last edited:
jej_knowles - looking at you case and the layout of components, I would also run the system as you have outlined it in the red line.

As Legion has explained, position of the rads etc. are not that important.
Go with what you have got, it will give you good temperatures & look neat.

Good luck with your project.
 
its statements like this that confuse me! lol!

Flow order doesn't make much difference at all. Obviously the first components in the loop will be cooler than the later ones, so put the components you want to be the coolest in your loop first.
 
thanks for the reassurance guys just needed to make sure i was on track with my planning.
@Legion , I have no idea how many/size of rads needed but im using sr-1's with nice quiet fans so hopefully i will have excellent cooling with only a whisper from the fans!
 
jej_knowles said:
@legion , I have no idea how many/size of rads needed but im using sr-1's with nice quiet fans so hopefully i will have excellent cooling with only a whisper from the fans!
Click to expand...

You have enough rad power there for an i7 @4+ghz and sli gtx 480.
 
Last edited:
NathWraith said:
Flow order doesn't make much difference at all.
Click to expand...

this is true enough.

Obviously the first components in the loop will be cooler than the later ones, so put the components you want to be the coolest in your loop first.
Click to expand...

but this is garbage.

Were one to obsess over temperatures to the extent that a tenth of a degree matters, the conclusion is to put the sensitive component after the radiator, as temp drops across the radiator. Not after a pump that actively dumps heat into the water.

I assume we're here to learn, authoritatively spreading misinformation conflicts with this. It also hurts the credibility of ocuk.
 
last post is lol, people do make mistakes. And how will that ruin the credibility of ocuk? Not everyone knows everything about computing.
have you never ever been wrong john?
I of course agree that the pump should be before the rad as it does dump heat into the loop.
 
It's a simple rule really.

Reservoir before pump. What comes after makes so little difference it really is not worth worrying about.
 
Yet heat dump is pretty minescule from the pump :)

I often get lambasted/questioned/etc for my loop order and fan direction on radiators but often I have found that hypothetical advice based on theoretical concepts or testing that isn't on my exact equipment just doesn't apply.

So I advise this, plan on putting your loop together, and plan on pulling it apart sooner or later to try things the other way around. Plan on it being a royal PITA to do and plan on everyone having different experiences and advise.

But only plan on that stuff if you give a monkeys about the last few degrees of temperature or if you are running stuff that pushes your cooling design to the limit or if you just like to tinker till everything is as optimised as it will get :)

That being said, as asked I'm quite happy to lend the benefit of my experiences :eek:
  1. Loop order doesn't make a hell of a lot of difference to temperatures
  2. GPU's get more from water cooling than CPU's, i.e. the temp drop is more effective
  3. #2 means that for me its more important to cool the CPU (in the case of i7's) because mine are always overclocked.
  4. These days I get the best results pushing highest pressure of the flow cooling the hottest part first so I go Res->Pump->CPU->gpu/mobo->rad->res
  5. What I find more important than loop order is keeping
    a) your 90° connections at a minimum (use straight or 45°'s wherever possible)
    b) your tubing lengths as short as possible
    c) your internal heat levels as balanced as possible (fan direction)​
You have a pretty good ratio of radiators to hardware so you should be able to keep it all nice and cool and quiet.

Good luck and keep us all updated!
 
Last edited:
domthecondom said:
last post is lol, people do make mistakes. And how will that ruin the credibility of ocuk? Not everyone knows everything about computing.
have you never ever been wrong john?
Click to expand...

I'm frequently wrong, though i do my best not to be. It's reasonable to believe that one staff member making silly mistakes reflects poorly on his employers.
 
You must log in or register to reply here.
Back
Top Bottom