Question about my loop

[shiroko]

Hello,

I had a single bay reservoir with my rad to cool my CPU, the loop was as this :
CPU > RAD > Bay reservoir > CPU and the coolant was nicely filled into the tubes when, the PC was running or OFF.

I wanted to add more coolant into the loop to help keep the temperatures low and decided to add a reservoir to store the coolant before the RAD and make the loop as follow : CPU > Tube reservoir > RAD > Bay reservoir > CPU.
As long as the PC is running the fluid looks nice and fill all the tubes.

But when I turn off my comp, the fluid is not filling the tubes completely anymore. Also I'm not sure the tubular reservoir should be that full ?

Thanks in advance for your help / advices !

Shiro

 

[oG AnarCHy]

You don't have enough fluid in your loop you need to add some until it's completely filled

 

[shiroko]

Hello and thanks for the quiick reply,
I though it was because the tubular reservoir was lower than CPU WB...
So I need to twist the case and fill it then ?
Also I see many tubular reservoirs filled to 3/4 not full, and when the loop run it make like a little waterfall (you can see tyhe fluid falling from the hose into the reservoir) but mine is filled up to top, is it normal ?

 

[Mandrake4565]

You definitely need to add more fluid, the bottom reservoir is filling up completely because it's below the pump and at the low point of the loop. How much fluid is in the bay reservoir when it's running. Also where is the pump, in the bay reservoir? You may also want to ditch the coolant, distilled water with biocide and or silver coil is the best way to go. It will give you better temps and a lot less maintenance.

 

[shiroko]

Hello Mandrake4565,

Yes the pump is in the bay reservoir and the reservoir is full of coolant.
Below are the pictures with system running and off :

And by the way I have a nickel plated EK waterblock, as per this report, they advise not to use water + silver coil :

http://www.ekwb.com/shop/EK-IMAGES/EK_STAINING_TEST.pdf

 

[Mandrake4565]

Well I would fill the top reservoir up a bit more while it's running, either pull it out a bit so you can get to the fill port or figure out another method to fill it up a bit more.

Second I've been using the Ek Supreme Hf cpu block with distilled and biocide in it without an issue. It's your loop, so you can do what you wish. That said, make sure you pull the loop apart regularly and clean it, at least every six months. That "coolant" will cause build up in the loop, increase temps and impede the flow.

 

[Pierre3400]

In all honesty, i would in any case change the loop.

Why store the liquid that have been cooled by the rad, in a res thats inside the pc, where heat is around it.

I would make the loop, Bay/res/pump > Rad > CPU > Res > Back to your Bay/res/pump.

With that said, i fail to understand why you want so much res in such a small loop.

 

[shiroko]

@ Mandrake4565,

Ok, I'll try fill it a bit more and btw I said silver coil not biocide
I might try distilled water + biocide in my next loop with a colored tube, for now I wanted to give a try on mayhems coolant (pastel line) I've already ordered.

@ Pierre3400, I'll try your loop as well and to answer your question, the bay reservoir didn't contain enough coolant to my taste, so I wanted to add more room to store more coolant. I bought the tubular reservoir for nuts and didn't want to buy a pump as the the one I have in my bay reservoir works like crazy.

But yeah, I could remove the bay reservoir, buy a new pump but I might go for a full cover on my GPU. The only thing is that no manufacturer makes any for this particular model... It's a MSI n770 tf 2gd5/oc

BTW if you know anybody who can make one please let me knooooow, otherwise I'll have to sell my GPU (3 months old)

I should have checked b4 buying it, I know

 

[Mandrake4565]

Ok, I'll try fill it a bit more and btw I said silver coil not biocide

I know, the report you linked also showed they found deposits and or staining with distilled and biocide. Interesting how EK is saying by using their coolant you wont have any problems. Mayhams Dye is probably the best stuff out there, but you may still have issues with clogging be diligent with cleaning the loop and you wont have issues.

 

[shiroko]

@ Mandrake4565, I toll agree with you. I prioritize companies focusing more on their product rather than packaging / advertising / marketing such as EK.

 

[bob4933]

Word to the wise, if you want any kind of decent serviceable life out of your system, mount the pump under the reservoir, not above it. Cavitation can destroy your pump pretty quickly, especially one that small.

 

[shiroko]

Hello bob4933,

Thanks for your input. Never heared about cavitation O_O
Could you please tell me how this occures and why having a pump under the reservoir can prevent from it ?

Cheerz

EDIT : nvm I g****d it

 

[bob4933]

Hello bob4933,

Thanks for your input. Never heared about cavitation O_O
Could you please tell me how this occures and why having a pump under the reservoir can prevent from it ?

Cheerz

EDIT : nvm I g****d it

gah, haha how deep do you want?

I will give you the sesame street version. Basically, when you mount the pump above the reservoir, you are limiting whats called "pump head". The output of a centrifugal pump is based entirely on pump head. If you have low pump head, you aren't putting out much pressure or volume. On top of this, with a low suction pressure, the coolant will actually drop pressure and create bubbles on the impeller of the pump (the part that spins to move the coolant), and over time this will DESTROY your pump. Not "it might happen", it WILL happen. The question is simply "how long?".

Not to mention, if you put it lower, your pump will operate more efficiently, which means higher flow, which means lower temps (theoretically). Its truly in your best interest to get that system layed out a little better. It doesn't have to be completely below the reservoir, but the lower the better.

 

[shiroko]

WoW very interesting, didn't know about it...
That's why I see a kind of foam forming in the bay reservoir since I added the tubular one.
I have to invest in a pump then (when this one dies).
The other thing is that the pump is integrated in the bay reservoir... I might resell it as it still works fine too, dunno

 

[bob4933]

Forgive the crude ms paint skills haha.


Is this possible? This would be the best setup for that system. If you mount the radiator in a pull fashion, and the fans for intake, this would be the best setup for that particular system

 

[shiroko]

rofl wtf lol

From what I understand :
Loop becomes bottom pump > tubular reservoir > rad (moved to top of the case)
That won't be possible as I run a 200 mm rad push pull mounted, I will have to buy a new one :/
The only thing I could probably afford is a pump, but do I keep the bay res in your schematic or do I skeep it ?

 

[S_I_N]

thermal dynamics predicts no amount of extra water will help make things cooler. All you've done is complicate your loop and add about 3-5 mins before water temps even out. Its simple physics at this point.

 

[Mandrake4565]

Word to the wise, if you want any kind of decent serviceable life out of your system, mount the pump under the reservoir, not above it. Cavitation can destroy your pump pretty quickly, especially one that small.

Bob is right about the cavitation and you're seeing foam or bubbles in the loop because the pump is sucking in air. This is because you don't have enough fluid in the loop. The pump being in the second reservoir which is at a high point, when running doesn't have enough liquid in it is sucking the air. Make sure you have enough fluid in the system and problem solved.

 

[bob4933]

rofl wtf lol

From what I understand :
Loop becomes bottom pump > tubular reservoir > rad (moved to top of the case)
That won't be possible as I run a 200 mm rad push pull mounted, I will have to buy a new one :/
The only thing I could probably afford is a pump, but do I keep the bay res in your schematic or do I skeep it ?

Take out the resevoir and move the pump to the bottom then. Those fancy bay reservoirs are so dumb. They look cool and crafty, but totally negate the point of pump systems.

Mounting the radiator at the top only makes sense honestly. if you cant do it, you cant do it, but its most important you get a full loop and try to get the pump down as low as possible.

 

[m0r7if3r]

Hello bob4933,

Thanks for your input. Never heared about cavitation O_O
Could you please tell me how this occures and why having a pump under the reservoir can prevent from it ?

Cheerz

EDIT : nvm I g****d it

gah, haha how deep do you want?

I will give you the sesame street version. Basically, when you mount the pump above the reservoir, you are limiting whats called "pump head". The output of a centrifugal pump is based entirely on pump head. If you have low pump head, you aren't putting out much pressure or volume. On top of this, with a low suction pressure, the coolant will actually drop pressure and create bubbles on the impeller of the pump (the part that spins to move the coolant), and over time this will DESTROY your pump. Not "it might happen", it WILL happen. The question is simply "how long?".

Not to mention, if you put it lower, your pump will operate more efficiently, which means higher flow, which means lower temps (theoretically). Its truly in your best interest to get that system layed out a little better. It doesn't have to be completely below the reservoir, but the lower the better.

Bob is right about the cavitation and you're seeing foam or bubbles in the loop because the pump is sucking in air. This is because you don't have enough fluid in the loop. The pump being in the second reservoir which is at a high point, when running doesn't have enough liquid in it is sucking the air. Make sure you have enough fluid in the system and problem solved.

I want to clear this up...because there's some stuff in here that's pretty wrong.

Firstly, when your pump is cavitating, that just means it's sucking air, no more. Water is incompressible, so you won't be able to make bubbles out if it without there being air in the loop already...shy of supercavitation at least. This is bad because the pumps that we use for WC are largely based on ceramic bearings which rely on the fluid they are pumping to cool and lubricate the bearing. Run dry, the pump can fail quite quickly.

Secondly, the location of the pump in a closed loop generally won't matter...certainly not in the case of the pumps that we use in any common computer case. You're talking about the pump's head needing to overcome restriction because it's at a high point, but this is incorrect. Any fluid that it fights gravity to move up eventually gets a gravity assist back down, this is the nature of the closed loop.

If you have your res immediately before your pump (which it should be, and in this case is an inherent feature of the res/pump), it does not matter where in the loop your pump/res is located. Air naturally tries to work its way to high points (flow in the loop can move it from these points, it won't just sit at high points), so if you have your pump near a high point and the res is not immediately before it, then you can run into issues of sucking air through the pump...which, as I mentioned earlier, is bad.

Hopefully that clears some stuff up. Feel free to have reasoned discussion on this.

Moving to your actual issue, I'm relatively certain that you've got it completely misdiagnosed. I believe your issue is two-fold. Primarily your issue is that your loop has a lot of air trapped in it. When your pump kicks on, your res levels probably change pretty significantly as the air is compressed. You don't see the air when it's running because it is pushed into your rad. When you reconfigured your loop, you did a poor job of bleeding it, and with your rad setup with barbs down, it's a big air trap (you can get around this, barbs down is fine, you just have to know how to work around it). The second issue, which I think is worsening the first, is that by bracketing the rad with reses (which is to say running res->rad->res), I suspect there is a strongly averse effect on flow. On the WC board (why isn't this posted there?) we had a long discussion about this the other day, and arrived at no real conclusion, but I'm of the mindset that reses should feed into each other...essentially creating one giant res.

Read up on how to bleed your loop, our sticky in the WC section is great, and try to get that air out of your loop and see if anything changes. Also, it may be worth reconfiguring your loop again, and removing the new res, or changing the loop order if you like the aesthetic of it.