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Mirco res bleeding issue

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May 14, 2012

After reading large amounts of content on this site, i finally purchased and built my cpu loop in my new Fractal Node804 case.

I am having a slight issue however that i am hoping someone can shed some advice on.

The issue is regarding the Micro tube res and DDC pump.

I am currently trying to bleed the system, however it seems like due to the short length of the tube res, the air is getting sucked back into the pump before it has time to surface..

It has been running for about 2 hours with the 1 fill cap off and it has gotten a little better but still no where near perfect.

Video attached..

Out of curiosity i did boot the system and gamed for a while and temps went from 80c on air to 54c on h20 which is great but i feel the air in the system will be screwing my results a little.. plus the pump is still noisy due to the air..

Is there any way to resolve this ? or get rid of some of the turbulence or air being sucked right back into the pump ? I see some of the tube reservoirs come with some foam piece that sits on top of the inlet to the pump section? i do not have this.. wondering if i could make one or if it would help allow some of the air to surface rather then get sucked into the pump..

specs: intel i5 6400 @ 4.2Ghz
GTX 970 Evga acx2.0
8gb gksill ripjaw

Thanks in advance!!
Let it run. It'll straighten itself out. ;)
2 hours isn't long enough.
Taking a chance on no leak test ain't ya?
Yeah that was silly, curiosity got me.

Anyway, let it run for 24 hours propped up to force the air to the fill port.. and it all worked its way out ... i guess the micro res simply took longer than the bay res i used years back..

Thanks again!
Yeah that was silly, curiosity got me.

Anyway, let it run for 24 hours propped up to force the air to the fill port.. and it all worked its way out ... i guess the micro res simply took longer than the bay res i used years back..

Thanks again!

Yup. That's usually the case. I had a micro res and it took much longer to bleed versus the big dual bay reservoir which gave me room to amp up the pumps. Some designs are better than others but usually a sponge does the trick and is designed to catch them bubbles before attempting to return to the loop.

Glad it all worked out. :salute:
haha thanks.

Only one more issue now..... due to fun and performance results from this loop... i am itching to get a GPU block for another weekend project :clap:! The hard tubing looks pretty slick too.... might give that a try..

likely going to grab an EK block as it seems they are the only vendor making full block for EVGA GTX 970 ACX 2.0

Final result (sorry, image was too large for local hosting)
Make sure the exact model is found in EK's coolingconfigurator for a perfect match or you run the risk of getting the wrong block if say, it wasn't a reference or a new revision.
Thanks GTX, i used their coolingconfigurator to get the correct block.

Onto a new question regarding micro res.. i purchased an additional 120mm rad to accommodate the heat the GPU block will dump into the loop (i now have 1x 120mm and 1x 240mm rad).

Question regarding res placement, the only place i can find to easily mount the res pump combo results in the res sitting directly in front of the 120mm rad and hot air from the rad will be directly blowing onto the res / ddc pump.

Is this a bad idea? i feel like it will be heating the water up within the res.. and further more.. the air moving over the ddc pump will be hot and i have been reading that the ddc pumps with no heat sink on them could have shorter pump life ?

Am i just getting paranoid now? would the heat from the rad blowing directly into the res be enough to screw temps up?

There is an alternative but it requires the res / pump combo to be mounted horizontal which i have seen people do... but i would rather not if i can get away with it..

Thanks again! Rad.jpg
Last edited:
Yeah i was debating that, but i would need to flip both sides around or else one rad would suck in hot air from the other... also from what i was reading it was best to push cool fresh air through the rad rather than the warm case air.

The node804 is pretty small and seems like limited options for placement of things..

attached a photo of the front rad mounts so you can see what i mean regarding the radiator sucking in hot air from the other..

I think i am going to mount the 120mm rad up top, pushing cold air through the rad and exhausted out the rear, then mount the pump in the front where the 120mm rad currently is as this will prevent hot rad air from blowing over it ..

I don't think it will be an issue but it might warm your water temps a bit.

Why not just use the bottom 120mm spot for the res/pump combo with some angled fittings helping you route and figure out a way for a drain while you're down there as well.

Also, you airflow configuration is fine. Intake from the front and out the back. It won't be extremely hot air being blown through. Its just warm, if it ever gets that warm. As long as you have good airflow, water flow and cool ambient temps, you should be good.
Well, here is the final result.. very happy with the system :D.

Temps are insanely low compared to my old air setup !

intel 6400 @ 4.2Ghz 1.26vcore
bumped gpu mem by 600Mhz on memory and 150Mhz on core..

Temps are both mid-high 40c while benchmarking.. CPU hits low 50's after a few hours of witcher 3. i was previously pushing into the 80c range on both CPU and GPU so there was MAJOR temp reductions here.

Thanks again to everyone that assisted with placement and res questions.

I already want to look at the hard tubes for a new project.. but that will be ways away... lesson learned was to never use pliars on the compression fittings ..as they rip the paint off and look like crap after :)

PCfront.jpg PCback.jpg
I would not trust that in the long term. You have lots of stress on that tube from rad to res and the pump is hanging off of it.

This is a disaster waiting to happen.

Support the pump and get a proper length of tube in there.

Glad the temps are working out.
I know thats how it looks from the photo,

but i have screwed it to one fan mount and added a zip tie to the opposite side, the tube is pulling a little but its not hanging from the rad.