Tips for complex water cooling loops

[J7SC_Orion]

After building complex w-cooling loops for work-and-play machines for most of the last decade, I thought some 'tips' for more complex loops could be helpful. Some of what I describe below is just based on personal preference on how to do things, while other steps are tried-and-true I learned either the hard way, or from other water-coolers over the years... 

  

  

 

The most important steps - after you pick and match your components (such as fans and rads) - is layout planning and prep work...and a bit of caution !

 

I like to watch complex HEDT builds on YT, but it never ceases to amaze me how even seasoned builders can skip a few important steps. For example:

 

- when taking out PCIe cards (GPU, other) from their boxes, they touch the 'gold fingers' of the cards with their bare hands, then plug them into the motherboard. May be I am paranoid, but I always make sure NOT to touch those gold fingers with my hands unless I wear a glove

 

- Speaking of paranoid, I flat-out refuse to use pastel-fluids for a water-cooling build. They can look fantastic, but unless you pull apart your loop at least once a year and thoroughly clean it, you are more likely than not to get various deposits, especially in complex bends, fine-grain copper fins and such.   

  

- another pet peeve of mine is watching folks install factory fresh (or for that mater used) water cooling gear such as rads, CPU and GPU blocks without flushing them first...I have never had new (even brand-name) radiators or GPU / CPU blocks that I did not carefully flush first...most of the time, they leave crud and other debris on the freshly-scrubbed bathtub floor after flushing. Using a white surface to be able to make out little pieces of debris is helpful - also to know when you are done.

 

- flushing can be done with a funnel and tap water, but once everything is thoroughly cleaned, an extra round or two of distilled water should be used for the final flushes...

   

 

  

  

  

  

...when working with used water-cooling bits such as pumps and fittings, a visual inspection and Q-tip cleaning might also be required...  

 

 

 

 

 

Edited December 21, 2020 by J7SC_Orion

[J7SC_Orion]

...once the flushing is complete and you plan on a very complex loop/s (example here is a dual loop, quad D5 pump, dual GPU, five rad build), it is best to test out components individually on a simple test bench..

   

  

   

  

...then do a test layout for the pumps (always below the reservoir to stay fed), using temporary tubing, especially when working with a combo of flexible and hard tubing (such as copper). Also note that the pumps are mounted on rubber pads - that will help greatly later on with noise and vibration...also note the blue bit of rubber tube slung around a metal L-piece that will go onto the bottom of the rad later on...

  

 

  

 

 

Edited December 20, 2020 by J7SC_Orion

[J7SC_Orion]

Layout checks should extend to cabling, fan hubs etc. I actually take and keep photos of that, especially when it is all hidden later on (here 'inside' the two-part back wall of a TT Core P5...before actual cable management with tie-downs). That way you will know the exact location of hidden items when you get back to maintenance a year++ on...

 

Also note the use of good quality, high flow Quick Disconnects...when used within reason (re. flow restriction), they impart a real advantage from a variety of perspectives (substituting other cooling on a temporary basis, loop maintenance or component exchange w/o full draining)   

   

  

   

Edited December 21, 2020 by J7SC_Orion

[J7SC_Orion]

Some fittings are better than others re. quality depending on the manufacturer, but I find that on average, they tend to last a long time when correctly installed and maintained. I would advise a bit of caution re. rotating fittings...I do use them (for example the 45 degree rotating fittings below on the TR CPU block) to make routing easier and flow less restrictive. But when installing them, make sure that there is no tension on them in one direction or another, or there could be a leak later on...also, once I install the rotating fittings, they never get, well, rotated and just stay where they are...

   

  

  

...finally, I use 'plumber's tape' (thin, flexible Teflon tape) on every fitting (except QDs of course). This also helps with well-tightened water-cooling fittings coming loose, for example after a week of benchmarking and heat-cycling a new build.

 

Speaking of that, I also check the CPU block screws / bolts after repeated heat-cycling...on more than one occasion, they had loosened just a bit after a week or so of heavy use and heat-cycling.

 

Edited December 21, 2020 by J7SC_Orion

[J7SC_Orion]

Once it is all planned out, assembled and thoroughly tested (including leak, flow, pressure testing, benchmarking and post heat-cycling tests), it is time to enjoy your system for years to come, with regular checks on temps and fluid levels, nothing more...loop water temp and flow meters are a good idea, though I do not always use them as I check temps (adjusted for ambient) regularly 

 

As to the fluids, I mentioned above that I completely avoid pastel colour fluids (never mind mixing different types of those). That holds especially true for complex custom water-loops - those with multiple pumps, lots of bends, multiple cooling blocks with narrow-spaced fins, and rads. Personally, I have been using TT's Pacific 1000 liquids for years (multi-metal compatible, with biocide), along with about 30% or so of distilled water. Other folks swear by other brand liquids.

 

An important tip for complex loops...just the GPU loop below has 3x 360/60 XSPC rads, dual D5 pumps and dual 2080 Ti GPUs. Filling and especially bleeding of such a loop can be a bit of a nightmare... once final assembly starts with all pre-fitted, cleaned and tested components, I actually pre-fill the 3 rads and tubes with the cooling liquid mix first, then make the final connections to close the loop and top it up. This helps to cut down the final fill and air bubble bleed time dramatically. 

 

However, as was the case in the first post re. touching the PCIe card gold fingers with your bare hands, I advise wearing a face mask and gloves when pre-filling a loop with still-open connections - it makes no sense to flush all the bits with distilled water before installation, only to cough on the still-open bits, liquids and such, or touch the inside of fittings and tubes with your bare hands...

 

    

Another question I sometimes get on my water-cooling builds is why I use separate loops for CPU and GPUs, and why each loop always has two D5s. The first part of the question relates to the complexity of a build - while more cumbersome to set up initially, a dual-loop is easier to upgrade (i.e. with new GPUs) and maintain, especially with strategically placed QDs.

 

The second part is heat management...modern D5s etc have a lot of power and move the liquids fairly rapidly - yet dividing an 1200+ W workstation / 4K gamer into two loops makes heat management easier...these days, most new CPUs and GPUs have boost algorithms that are heavily affected by temps, and good heat management pays handsomely... 

 

As to two D5s per loop, that is not absolutely necessary - though it certainly does not hurt either. I always use two D5s per build for fall-over reasons...while I never had a D5 fail in operation (all the ones in the build below are 7+ years old), it is basically just 'habit' from also building high-use servers with which any downtime is costly...

 

...a second D5 is cheap insurance, in addition to helping flow and pressure...in fact, there are tests that show that dual D5s avoid the 'starvation' and related pressure drops that can sometimes effect a singe D5 due to its larger diameter (when for example compared to a single DDC pump).

 

Finally, the loop part sequence layout is not as critical as is sometimes assumed, as long as the reservoir sits above the pumps, and sharp, restrictive bends are avoided. D5s can move a lot of liquids fast and pressure tends to equalize. Still, even for aesthetic reasons as well as slightly improved pressure and temps, the GPU loop used as an example here has a D5 right before each of the two GPU blocks as those tend to be the most restrictive in a loop.

  

The TR workstation + 4K gamer below has a lot of complex and hidden water-cooling components (total of 5 big rads, 4 pumps, 3 blocks, 20 fans...) yet has been running cool and without any trouble for almost two years now (even been on 3DM HoF now for 1 1/2 years). The prep work I described above not only helped with temps but also to 'hide' a lot of the related tubes, pipes and cables, a bonus since I look and use that system every day...

    

 

 

 

 

Edited December 22, 2020 by J7SC_Orion
typos edits etc

[mouacyk]

I like to leak test complex components like gpu and cpu blocks by themselves with an air pressure test kit.  Otherwise it's harder/messier to identify the leaking part without actually seeing leaks. 

[J7SC_Orion]

...makes sense, but one still needs all final connections (fitting, tubing etc) to be made to test the whole loop's integrity. Leaks, if any, are more likely to occur in the connecting bits...best to do both, perhaps 

[Kimir]

Yes, absolutely recommend a full loop air leak test. No towel and no mess when filling it up. 

[ENTERPRISE]

Great advice ! I always do a RAD flush if I am installing a new one into the loop. My leak tests are done with liquid as while a little more risky, for me it is far easier to identify the location of a leak.

 

Once thing I always tend to do, possibly a little over the top, but anytime I add anything to the loop such as GPU etc, I tend to flush out the system with a Mayhems Blitz Kit to ensure a clean loop but more importantly to ensure everything in the new GPU block is "Dead" and clean before re-introducing coolant.

[J7SC_Orion]

12 hours ago, ENTERPRISE said:

Great advice ! I always do a RAD flush if I am installing a new one into the loop. My leak tests are done with liquid as while a little more risky, for me it is far easier to identify the location of a leak.

 

Once thing I always tend to do, possibly a little over the top, but anytime I add anything to the loop such as GPU etc, I tend to flush out the system with a Mayhems Blitz Kit to ensure a clean loop but more importantly to ensure everything in the new GPU block is "Dead" and clean before re-introducing coolant.

 

Good advice re. Mayhem's Blitz kit. That said, I even use distilled water to do a flush after the Blitz kit...  

 

[Diffident]

Don't do this.

 

Fill and leak test without powering any components.

[J7SC_Orion]

3 hours ago, Diffident said:

Don't do this.

 

Fill and leak test without powering any components.

  

...yes, thou shall make sure thy loop is closed before you turn it on  

[ENTERPRISE]

15 hours ago, J7SC_Orion said:

 

Good advice re. Mayhem's Blitz kit. That said, I even use distilled water to do a flush after the Blitz kit...  

 

Yeah I left that out, I also do a "rinse" of the loop ...a big one before popping in replacement cooling.

[J7SC_Orion]

...

 

  

  

[Chiraq]

As for simplicity  I like to just run a single loop with 1/2" minimum tubing. I did the parallell stuff for a while but found that as long as you have enough flow and volume the temps dont differ much from heatsource to heatsource.  

[Mistio]

Bookmarked!
I have cash to the side for a Rocket Lake / Alder Lake Full WC build :). 

[J7SC_Orion]

9 hours ago, Chiraq said:

As for simplicity  I like to just run a single loop with 1/2" minimum tubing. I did the parallell stuff for a while but found that as long as you have enough flow and volume the temps dont differ much from heatsource to heatsource.  

  

Fair enough...I have air-cooled, AIO, simple single loop and complex loop systems here...but I titled the thread specifically for complex / multi loops as the approach is a bit different when having to deal with over 1,100 W heat energy, multiple restrictive blocks etc in a build. Then there is the fail-over  / redundancy I mentioned above for servers etc.

 

Nothing wrong with a simple loop - I writing this post on one...all just depends on the use-case and number of components and their heat output.  

[Sir Beregond]

I'm just doing a simple loop. CPU, GPU, 2 rads, pump/res. 

 

I think this is well written and good advice for all. The one part where I am faltering is that I really would like to try a hardline build and the new white Meyhems fluid is looking interesting. But may also just say nuts to that and stick with my white Primochill tubing and clear X1. I don't know...The shallow part of me is starting to take over lol. Alternatively may just look at sticking to clear and painting the tubes? Not sure.

 

In the past I had always flushed with hot tap water and then several rounds of distilled. My last build had a lot of debris problems and then plating flaking (but I think that's just down to crappy EK blocks). I bought a Blitz kit for the upcoming build and plenty of distilled for flushing after that is done.

Edited February 12, 2021 by Sir Beregond

[Paradigm Gaming]

Amazing thread, thanks to the OP

 

This thread contains high quality information for building water loops.  I'm a complete lover of complex and dynamic water loop challenges, opting most often for dual loops and most often in cases that allow tubing to flow through the back of the case as well.  I love the optics of mixing hard bending with fittings bends and have just gotten into straight glass w/fitted bends.  

 

Reading through this, there's only 2 things that I think I can focus on that might help.  Through my trials and tribulations of building and water cooling, I learned over time the importance of learning how to distinguish between air flow fans and high static pressure fans.

 

The more complex the water loops, the more reliant on your radiator fans you'll be for them to cool water that is generally flowing over a greater distance than it would in a simple loop.  

 

I tend to build in cases that allow for push/pull radiator configurations to maximize the airflow component of the cooling process.  Use air flow fans for exhaust and intake where radiators are not located, but always use high static pressure fans for your rads.  If your fans don't have the static pressure to compress the air and force it through the radiator fins efficiently, it will do a disservice to the beautiful complex water loop you just designed.  

 

Second, no matter the fluid I use in the end, I always water test my loops with UV Clear Blue.  Using UV Clear Blue, you only need to look over your connections and loop with a UV flashlight to check for leaking.  Any leaks will glow big and bright blue for you to see.  Then I flush and use the fluid I want to build with.

 

I love think tank and information sharing threads.  Thanks all

[ENTERPRISE]

1 hour ago, Paradigm Gaming said:

Amazing thread, thanks to the OP

 

This thread contains high quality information for building water loops.  I'm a complete lover of complex and dynamic water loop challenges, opting most often for dual loops and most often in cases that allow tubing to flow through the back of the case as well.  I love the optics of mixing hard bending with fittings bends and have just gotten into straight glass w/fitted bends.  

 

Reading through this, there's only 2 things that I think I can focus on that might help.  Through my trials and tribulations of building and water cooling, I learned over time the importance of learning how to distinguish between air flow fans and high static pressure fans.

 

The more complex the water loops, the more reliant on your radiator fans you'll be for them to cool water that is generally flowing over a greater distance than it would in a simple loop.  

 

I tend to build in cases that allow for push/pull radiator configurations to maximize the airflow component of the cooling process.  Use air flow fans for exhaust and intake where radiators are not located, but always use high static pressure fans for your rads.  If your fans don't have the static pressure to compress the air and force it through the radiator fins efficiently, it will do a disservice to the beautiful complex water loop you just designed.  

 

Second, no matter the fluid I use in the end, I always water test my loops with UV Clear Blue.  Using UV Clear Blue, you only need to look over your connections and loop with a UV flashlight to check for leaking.  Any leaks will glow big and bright blue for you to see.  Then I flush and use the fluid I want to build with.

 

I love think tank and information sharing threads.  Thanks all

 

Great advice, out of interest what would you suggest as a premium fan with respect to high static pressure ? I have been using my Noctua's for now : https://noctua.at/en/nf-a14-industrialppc-3000-pwm 

 

Awesome fans but not sure if best ? The specs looks decent enough on my fans.

[Paradigm Gaming]

40 minutes ago, ENTERPRISE said:

 

Great advice, out of interest what would you suggest as a premium fan with respect to high static pressure ? I have been using my Noctua's for now : https://noctua.at/en/nf-a14-industrialppc-3000-pwm 

 

Awesome fans but not sure if best ? The specs looks decent enough on my fans.

 

It's hard to ever go wrong with Noctua fans.  They were/are the elite of the static pressure fans.  I would have been a much bigger Noctua fan back in the day had I understood their affinity for the color brown.  They were never the best looking fans to me, but it's hard to argue with a fan that create static pressure in the 7 range.   Anything over 3 is going to really displace some heat.

 

Granted, all static pressure ratings are published at max fan speed, but anyone building a machine to push it to it's limits needs to know what that rating is at max speed.  

 

For everyday, heavy load gaming or rendering, I try to find a middle ground between what I know will work the best and what fits the aesthetic I'm looking for.

 

I'd advise anyone looking to build hardcore, overclocking and heavy load rigs that they are going to push to the edge to look at Noctua and Arctic.  I'd consider them the best of the best for static pressure.

 

For exhaust, I always try to marry high air flow rate and RPM with the aesthetic I need.

 

While lower static pressure rated than I'd like, my next build will be with Lian Li SL120's.  I'm completely enamored with their brilliant daisy chain design.   To be able to hard connect fans together like legos, without wiring, leads to so many build options.  The design allows you to control, or have the motherboard control, 16 fans through one header.  

 

They are expensive as f*** though, not much unlike Noctua's best offerings.

[ENTERPRISE]

15 minutes ago, Paradigm Gaming said:

 

It's hard to ever go wrong with Noctua fans.  They were/are the elite of the static pressure fans.  I would have been a much bigger Noctua fan back in the day had I understood their affinity for the color brown.  They were never the best looking fans to me, but it's hard to argue with a fan that create static pressure in the 7 range.   Anything over 3 is going to really displace some heat.

 

Granted, all static pressure ratings are published at max fan speed, but anyone building a machine to push it to it's limits needs to know what that rating is at max speed.  

 

For everyday, heavy load gaming or rendering, I try to find a middle ground between what I know will work the best and what fits the aesthetic I'm looking for.

 

I'd advise anyone looking to build hardcore, overclocking and heavy load rigs that they are going to push to the edge to look at Noctua and Arctic.  I'd consider them the best of the best for static pressure.

 

For exhaust, I always try to marry high air flow rate and RPM with the aesthetic I need.

 

While lower static pressure rated than I'd like, my next build will be with Lian Li SL120's.  I'm completely enamored with their brilliant daisy chain design.   To be able to hard connect fans together like legos, without wiring, leads to so many build options.  The design allows you to control, or have the motherboard control, 16 fans through one header.  

 

They are expensive as f*** though, not much unlike Noctua's best offerings.

 

I got worried for a sec then as I was sure I got appropriate fans for the rads lol, but was a while since I checked the fan specs.

 

Yeah Noctua is awesome but the original. Colour choice is not great.  Black with brown corners is what I have, so not bad. All black would be nice but didn't fancy forking out for a tonne of new corner pieces lol.

 

Push pull is something I would usually go for but my res is mounted to my front rad and my top rad would be a pain to put another set of fans on as it will interfere with my motherboard. 

 

Nice, I like being able to control multiple fans from one header, really saves on cable management etc. Sounds like the Lian Li has a decent setup.

[J7SC_Orion]

5 hours ago, Paradigm Gaming said:

Amazing thread, thanks to the OP

 

This thread contains high quality information for building water loops.  I'm a complete lover of complex and dynamic water loop challenges, opting most often for dual loops and most often in cases that allow tubing to flow through the back of the case as well.  I love the optics of mixing hard bending with fittings bends and have just gotten into straight glass w/fitted bends.  

 

Reading through this, there's only 2 things that I think I can focus on that might help.  Through my trials and tribulations of building and water cooling, I learned over time the importance of learning how to distinguish between air flow fans and high static pressure fans.

 

The more complex the water loops, the more reliant on your radiator fans you'll be for them to cool water that is generally flowing over a greater distance than it would in a simple loop.  

 

I tend to build in cases that allow for push/pull radiator configurations to maximize the airflow component of the cooling process.  Use air flow fans for exhaust and intake where radiators are not located, but always use high static pressure fans for your rads.  If your fans don't have the static pressure to compress the air and force it through the radiator fins efficiently, it will do a disservice to the beautiful complex water loop you just designed.  

 

Second, no matter the fluid I use in the end, I always water test my loops with UV Clear Blue.  Using UV Clear Blue, you only need to look over your connections and loop with a UV flashlight to check for leaking.  Any leaks will glow big and bright blue for you to see.  Then I flush and use the fluid I want to build with.

 

I love think tank and information sharing threads.  Thanks all

  

...some excellent points ! However I prefer not to mix anything into the final fluid combo before leak-testing. As I build both servers / workstations as well as fun machines, I have a setup with an external Molex that powers all the pumps etc for a new w-cooling build w/o having to turn the main mobo on. I let that run for several hours, power and cool down, than run for another few minutes - be that for a single loop or dual loops. More on fans below...

   

1 hour ago, ENTERPRISE said:

 

I got worried for a sec then as I was sure I got appropriate fans for the rads lol, but was a while since I checked the fan specs.

 

Yeah Noctua is awesome but the original. Colour choice is not great.  Black with brown corners is what I have, so not bad. All black would be nice but didn't fancy forking out for a tonne of new corner pieces lol.

 

Push pull is something I would usually go for but my res is mounted to my front rad and my top rad would be a pain to put another set of fans on as it will interfere with my motherboard. 

 

Nice, I like being able to control multiple fans from one header, really saves on cable management etc. Sounds like the Lian Li has a decent setup.

  

...I have a collection of the Noctuas - but that colour ! I use them for workstations that go into 'boxes', but for open builds, no thank you. I got so desperate on a personal TT Core P5 build that I actually spray-painted some Noctuas black (still work, btw).

 

...for benchers and heavy duty, I use the tried and true GentleTyphoon 4K rpm models, each w/ 183 CFM...they are for example on my GPU loop for dual 2080 Tis and they just keep everything below the first speed-bin loss...so far, I haven't been able to 'heat-soak' that GPU loop with 760 W in 2 years, and not for lack of trying !  

 

..we also have a big pile of repatriated Sunon 5K rpm server fans, but while they certainly cool very well, they just can't be used if you sit within earshot, whereby I find the GentleTyphoons 'somewhat bearable'  ...GT 4K on the left, Sunon 5K on the right:

   

  

...lately however, I have been getting into Arctic P12 pwm PST fans - and I'm genuinely shocked at the great price-temp_noise performance ratio, especially if you buy the 5 value pack. Obviously I don't know yet how reliable they are over the longer term, but they sure beat the cr_p out of for example Corsair ML 120s, both in terms of noise at full tilt, and temps w/ all other factors held equal.

 

I just put 5 of those into 'The Thing' (you know as the Strix 3090 OC testbench) - 3 for the CPU, and 2 for the GPU backplate (double-sided GDDR6X = toasty). When I watercool the Strix, I'll be using those. The question is whether they last as long as for example the GentleTyphoons (some of those are over 8 years old, & in continuous use...). 

  

 

 

Edited February 15, 2021 by J7SC_Orion

[Sir Beregond]

One thing I'll add to the discussion on radiator fans, yeah when talking maximum performance you are right on the money about static pressure and push/pull configurations.

 

Personally another facet/benefit that water-cooling affords is for those of us who absolutely hate fan noises. Still get proper static pressure fans, add enough radiator space to the loop, and you can run those bad boys at RPMs where you can barely hear them even under load. Maximum performance? No. But far better than air cooling and you can always adjust for those times you do want max performance.

 

Having a silent PC has addicted me to watercooling.

 

I do have one question though. Does push/pull really make more than a small difference in performance? I always thought it seemed kinda overkill, but if "pushing to the limit" I suppose it makes sense.

[J7SC_Orion]

3 hours ago, Sir Beregond said:

One thing I'll add to the discussion on radiator fans, yeah when talking maximum performance you are right on the money about static pressure and push/pull configurations.

 

Personally another facet/benefit that water-cooling affords is for those of us who absolutely hate fan noises. Still get proper static pressure fans, add enough radiator space to the loop, and you can run those bad boys at RPMs where you can barely hear them even under load. Maximum performance? No. But far better than air cooling and you can always adjust for those times you do want max performance.

 

Having a silent PC has addicted me to watercooling.

 

I do have one question though. Does push/pull really make more than a small difference in performance? I always thought it seemed kinda overkill, but if "pushing to the limit" I suppose it makes sense.

  

...re. your question as to whether push+pull makes a difference, 'yes', but it depends to some extent on the rad setup (thickness, fin density) and of course the fans themselves. I build my first quad-SLI back in '12 and used a custom 1080x60 rad (equivalent to MoRa360) with 18x static pressure fans, 9 at the front and 9 at the rear...the difference on that particular setup was about minus 5 -6 C for the CPU under load  but more pronounced when loading the Quad-SLI with benches. 

 

...same with the 2080 Ti SLI-CFR setup, it uses 3x 360/60 in push+pull with GentleTyphoons (and one w/ ML 120s in push pull)...static pressure isn't a problem and the resulting 'noise' is largely mitigated by baffles I added (which also help airflow, btw) as those rads sit 'on their side'.

 

Key is to have 'matched fans' running on the same controller - you don't want the fans to hinder each other 

 

...with the Arctic P12 PST I'm just getting into, installing them on one side dropped temps by over 4 C compared to the ML 120s - and the P12s are amazingly quiet even at speed...adding push/pull to those tomorrow in the new build and will update here  ...in the meantime, check this out:

  

 

 

Edited February 15, 2021 by J7SC_Orion
typo