Got questions on watercooling? Official WC FAQ

Xilikon · Jan 23, 2008

Here is the FAQ, which is still a work in progress but pretty elaborated (just missing the parts recommendation and where to buy them worldwide). I tried to put the most asked questions with the usual answers here so if you have more questions/answers,PM me and I'll add :

You got curious about watercooling or wanted to jump on it but don't know where to start? You are in the right place

Basic FAQ:

Q: What is watercooling?

A: It's a method to extract heat from the computer components and dissipate it in the air with water as a heat carrier. Unlike air cooling, which is basically a base with lots of fins (tied by either heatpipe or directly from the base) and dissipated with the help of a fan or passively, water is a more elaborate closed loop system comprised of those elements: a pump (to circulate the fluid in the loop), a reservoir (to hold the fluid and feed the pump), one or more blocks (to extract heat from computer components and transfer in the fluid) and one or more radiators (to dissipate the heat carried by the fluid in the air either passively or with fans).

Q: What are the advantages?

A: Since water has a much higher specific heat capacity (http://en.wikipedia.org/wiki/Specific_heat_capacity) and thermal conductivity than air, it is more efficient at extracting heat from components. This will also allow you to place the radiator anywhere you want for the most efficient heat dissipation unlike air cooling, where you are limited to the CPU socket area enclosed in a case with potentially hot ambient air inside. With a very good setup, you can have a much more silent setup than air cooling while getting more thermal dissipation.

Q: Is watercooling really safe?

A: When done correctly, watercooling is as safe as air cooling. When done poorly, watercooling is as safe as an underwater LAN party. The main thing to remember about a watercooling system is you have to be CAUTIOUS, you have to follow COMMON SENSE, and you have to TAKE YOUR TIME. When it's all said and done, there will be no real risk to your system. If you rush through setting it up, then you put your system in danger. Remember, most failures are due to human error and not a faulty component. A fan can die just as easily as a pump can die.

Q: How much is this going to cost?

A: Honestly, it's very hard to build a good setup under 100$ and be as efficient as the best air cooler but when you get past initial setup expenses, it can be very cost effective if you pick the right parts. With the right parts, all you need to change is the water blocks ONLY IF the block manufacturer doesn't provide a new mounting adapter or the block isn't efficient to cool a component. The expense of a block is the same as the price of a good air cooler at this stade.

This is why it's very important to take your time to do a research based on your needs. Don't be afraid to spend a bit more if this expense will warrant you a long term use of the setup (This is true on pumps, reservoirs and radiators, which rarely change even if the blocks get updated) and try to overshoot if you think you will be adding more blocks like video cards and chipsets/mosfet.

After all, if all you want is to cool the CPU and don't want to mess, don't bother with watercooling and stick with air cooling. It's basically a kind of hobby for computer enthusiasts since when you get the WC bug, you will want to tinker with it more

Xilikon · Jan 23, 2008

WC loop FAQ:

Q: How parts should be ordered in a closed loop?

A: Before talking about the order, the main rule is to ALWAYS put the reservoir before the pump because the current pumps will be damaged if it gets starved for water. Having the reservoir before the pump will ensure there is a constant supply of water and to trap air bubbles (more on it later).

Beside this rule, the order doesn't really matter and it's mostly user preferences. To determine a good order, there is 2 good advices : Try to put the block you wanted to cool the most (like a CPU block) immediately after the radiator so it get the coldest water and make sure your tubing is as short as possible so water doesn't travel too much. A recommended loop order you will often see in lots of watercooling setups is like that: RESERVOIR -> PUMP -> RADIATOR -> CPU BLOCK -> (CHIPSET BLOCK) -> (GPU BLOCK) -> BACK TO RESERVOIR (The items under parenthesis are facultative items).

Q: What is the best fluid to use ?

A: The best fluid we can use in a loop is pure distilled water with nothing else added. Pure distilled/deionized water have the best thermal properties of any fluid while not having anything which can cause issues (precipitates, dye staining, chemical reaction or acidity/alkalinity). For those who wanted to keep distilled water for more than 1 month should consider adding 1 or 2 drops of a biocide (copper sulfate like PT Nuke) to stop the growth of algae. If you need to add color, use a dye sparingly or use colored tubing to avoid using a dye.

There is pre-mixed fluids available in the market so it's tempting to buy them for the "cool" or no hassle factor. They often have the "non-conductive" marking on the bottle but don't get duped by this because no fluid is non-conductive, even plain distilled water (even if a fluid or distilled water is deemed non-conductive, it will become conductive over time due to the migration of metal ions in the water). It's also expensive and sometime poisonous.

About the anticorrosion additives like Pentosin G11, if you setup the loop correctly with the right parts, there is no corrosion risk (as outlined in the next Q/A about corrosion) so you don't need to add them. The only reason is mostly for color and less risk of biological growth if you keep it over a few months without flushing. In case you insist to use some aluminium parts, it's required to add them to mitigate the corrosion effects or you can risk voiding the warranty.

Q: Can I mix aluminium and copper parts in a loop? What is galvanic corrosion?

A: Without elaborating too deeply into the process, a galvanic corrosion is a electrochemical process where a metal will corrode when put in presence of a dissimilar metal in a electrolyte. Each metal alloy has a electrode potential and a electrolyte is a medium where ions will migrate from anode to cathode, causing the corrosion process. One of the ways to reduce galvanic corrosion the most is to try to mix metals with the closest electrode potential so there is virtually no ions migration. brass and copper are one of the closest because brass is a allow of copper with zinc but aluminium is very far from copper so it will act as the anode, losing ions. When aluminium act as the anode, it will dissolve and stick to copper, causing holes in aluminium and those holes will eventually get big enough to cause a leak.

So to answer the question about mixing aluminium and copper, the best one is to avoid aluminium like plague even if it's anodized or plated. With the current selection of watercooling components in the market, there is no reason to buy components with aluminium in contact with water. People will often say it's safe if you take precautions like using a anticorrosion fluid (a glycol, as in antifreeze fluid) and drain the loop pretty often but why try to use bandaid remedies if you can remove aluminium from your loop?

Q: How to pick the right radiator size?

A: It's indeed a tricky part but let me try to make it simple and use a few rules of thumb for basic selection. We know that the bigger the radiator surface is, the more it will dissipate heat in the air but you are limited by the ambient temp. There is no point trying to buy 10 radiators so if you wanted to cool your system below ambient, you will need to get to exotic cooling systems (chilled water, phase change, immersed in mineral oil or liquid nitrogen). The radiator surface is usually calculated by the amount of 120mm fan area so a 1x120 is the same size as a single fan, 2x120mm is the size of 2 fans together and 3x120 is 3 fans.

The actual heat dissipation capacity will depend on what fan to use so a silent/low-CFM fan will dissipate less than a high-CFM fan. The normal average is usually 50 CFM so with this in mind, a 1x120mm area will dissipate about 150w so a triple can dissipate a total of 450w. With this info in mind, the next thing to do is to calculate the total amount of heat dissipated by all the water blocks and the pump in watts then divide by 150w to get the amount of radiator surface.

If you want to be more precise and is not afraid to calculate the exact amount, there is a good page about that written by Marci (from Thermochill):
http://www.over-clock.co.uk/ivb/index.php?showtopic=20277

Q: Which is best between 1 120.2 radiator and 2 120.1 radiators in a loop?

A: Short answer : both are equally good since the total radiator surface is the same. Long answer : It depends on a lot of factors including the flow restriction, actual heat dissipation efficacity of a 120.1 vs 120.2 (doubling the surface doesn't always mean doubling the dissipation) and loop size. Ideally, it's best to get a single radiator with the biggest surface you can use depending on your case modding skills, ease of installation and price. If you aren't good at modding and/or your case cannot hold big radiators but have a few 120mm fans holes, you can get away with some smaller radiators but make sure you get those who are not very restrictive, like Thermochill or Swiftech.

Also, if you want to avoid a component heating the loop too much to cause issues to the rest, you can split in 2 loops. In that case, you have no chice to get 2 radiators so that question will become useless.

Q: Do I need to flush the components in a loop? How should I flush them?

A: When you receive the components new or used, it's a good idea to give a good cleaning. For the blocks, just disassemble them and clean them with a brush and some ketchup to remove oxidization and stains if you got it used (you can also use vineger if you think ketchup is gross). After the initial cleaning or with new parts, make sure you rinse them thoroughly with distilled water (don't use tap water as this will leave mineral deposits if you area have hard water) until it come clean then it's ready to be used. This is the same with a pump but skip the ketchup and/or vineger as it's not needed and only rinse it with distilled water.

The hardest part to clean in the loop is the radiator because you cannot open it. If you bought it new, it will have a lot of deposits in it, especially flux from the manufacturing process so you need to remove them but even used can have some residu from the cooling fluid or algae. The best way to clean them would be to use boiling distilled water so pour it in the reservoir outlet till it's filled up, leave it for 5-10 mins then remove half of it and shake it (make sure to wear oven mitts since it will be very hot). Do this for 6-10 times till the water come out very clean but it's possible you will need more. A easier way would be to buy a cheap submersible pump, put it in a kettle, connect the radiator to the pump then let it run for 1-2 hours till it come clean (just replace the water once or twice to help).

Some people will tell you to use vineger to clean it but don't do this since it's pointless and this will tarnish copper if you let it sit for a bit.

Q: I'm confused at the sizes of the barbs? What is G1/4" I see often in documentation and discussions?

There are 2 components in the fitting dimensions : The threading size and the tubing inner diameter. The G1/4" is the threading size, which is the same as 1/4" BSPP (British parallel plumbing threading) and it's currently the standard used in almost every watercooling component beside a few oddities (Thermochill radiators use G3/8" as example). The tubing side diameter is the tubing inner diameter size it can accept so logically, for a 1/2" ID tubing, you should be looking at 1/2" barbs. With compression fittings, things get more complicated because it will list the inner diameter and the outer diameter too so with a compression fitting, make sure you get the right one for the correct tubing (like 8mm/10mm compression fitting requiring 8mm/10mm tubing and nothing else).

Don't confuse BSPP or G1/4" with NPT which is often used in North America. If you want more information about threading standards, Google is your friend.

Q: Do I need clamps on the barbs? Which clamp is available and which is best?

A: It's always a good idea to have clamps on the barbs because there is always a risk of leaking if you don't use them. The only case when you don't need them is to use a undersized tubing on oversized barbs or if the tubing looks to be very snug on the barb but you must leak test to make sure it's ok before running the computer. There are a few options available to clamp and here is a good list : Worm Drive (also called Jubilee Clip), Nylon hose clamps and Zipties in the order from best to average. Zipties is good as long as you install it correctly and tighten them strong enough so the tubing won't pull off the barb but don't rely on them to seal them since there is always a gap around the mechanism. With worm drives, you should try to tighten just enough to make a snug fit but not too much since it can pierce or cut the tubing and/or crush the barb. Nylon hose clamps is a good alternative but make sure you get the right size or it won't work and if you try to tighten too hard, it will break.

Q: I don't like clamps, can I use compression fittings instead?

A: Compression fittings is a great way to fix the tubing to the blocks without using any form of clamping. It's also very nice to look for those who care about the looks. However, selecting the wrong compression fitting for your tubing can lead to disastrous results. To avoid this, first determine what is the tubing size you plan to use (both the inner and outer diameters) then make sure the compression fitting you select is made for the exact tubing size (if you select a 3/8" ID 1/2" OD, you must use 3/8" ID 1/2" OD compression fittings only). If the outer diameter of the compression fitting is larger than the outer diameter of the tubing, no sealing is possible and it will leak. If it's the other way and it's smaller than the tubing OD, you will have a hard time screwing the ring and risk cutting the tubing.

The most common sizes in the market currently is 3/8" ID 1/2" OD, 3/8" ID 5/8" OD, 1/2" ID 5/8" OD and 1/2" ID 3/4" OD so you are limited to those sized when selecting tubing.

Q: What is best between a reservoir and a T-line?

A: Each one has its advantages: A reservoir will help a lot with bleeding (remove air bubbles from the loop, which can prevent heat transfer) by trapping air bubbles better but it's a bit more cumbersome to install and you need a place for it. A T-line (a vertical line with a T coupler placed in a loop) is inexpensive and less cumbersome to install but bleeding will take much longer to do as it doesn't trap air that well. A T-line will also serve as a drain line if it is placed in the lowest part of the loop and long enough to be able to be moved out of case. In my opinion, if you can afford the expense and the room to have a reservoir, it's strongly suggested to get one and with the current choices, you have no real reason to avoid them.

Q: how to choose between a full cover GPU block and a GPU core only block?

A: Again, it's a matter of personal preferences and budget. A full cover block has the advantage to cover everything on a card including the core, memory, mosfets and the IO chip and get it cooled more than with air but it's a bit expensive to own and very often, it works only with a specific model of card. You cannot get a full cover block designated for card X on card Y as the mounting holes is different and the components might not be positioned the same for good contact. On the other hand, a GPU core only block will only cool the core so you are required to find other ways to cool the rest of the card with ram sinks, mosfet sinks and IO sink (screwed or glued with thermal pad/epoxy) and have some airflow over the surface to dissipate heat. However, since it's only for the core, you can reuse it in the future as long as the block manufacturer release the mounting plate or the holes fit. It's also less expensive.
Finally, a full cover block will let you avoid dumping the hot air in the case so it will help lower the case temp.

Q: Do I need a backplate to mount a block?

A: The main goal of a backplate is to avoid bending the board and ensure the mounting is as straight as possible. With a CPU block, having a backplate is a good idea since the mounting pressure is often strong enough to bend the motherboard. Bending the motherboard will possibly damage it or causing the mosfet (the chips around the CPU socket) to lose good contact with the heatsink and overheat. For the GPU, it's not necessary and usually, there is already one installed on the card or the full cover act itself to straighten the card. As for the chipset and mosfets, it depends on how it's mounted, how strong the mounting is and how easy it is to bend so you can fabricate some yourself or order from a place who have them.

Q: Can I put the radiator in a refrigerator ? Can I put the radiator outside ?

A: It's a bad idea since a refrigerator is built to cool food and keep it cool and not to continously dissipate the heat generated by a radiator. If you do this, you may see nice results at first but after a short while, the compressor of the refrigerator will fail. Beside this, if the water in the radiator is cooled below the ambient temperatures, you will have the risk of creating condensation and risk damaging the computer components without proper precautions (If you still insist on doing this, hop in the chilled water forum and ask since it's out of our scope). You can also risk freezing water and cause damage to the radiator and other components.

Xilikon · Jan 23, 2008

Specific parts FAQ :

Q: I have a Thermochill radiator and I cannot find the right fittings for it?

A: Good question, the Thermochill radiators use a G3/8" (BSPP 3/8") threading and the current barbs threading is G1/4". There is currently a few ways to get around this :

1- If you are in the US, you can order a pair of G3/8" to G1/4" adapters from http://www.mcmaster.com. Look for part 4860K657. With the adapter, you can use any G1/4" barbs or compression fittings you want. this is in my opinion the best choice, giving you the most freedom.
2- If you are in Australia, GAM sell G3/8" 1/2" barbs : http://www.gammods.com.au/store/index.php?main_page=product_info&cPath=1_91&products_id=4
3- In Canada, NCIX also sell them but they are a bit undersized for 1/2" tubing, ideal for 3/8" tubing only : http://www.ncix.com/products/index.php?sku=25389&vpn=63018&manufacture=Thermochill
4- Lately, a few manufacturers like EK and BitsPower started manufacturing G3/8" barbs and adapters so you have more choices.

Q: I have a D-Tek Fuzion CPU v1 block and the nozzles kit, what nozzle to use?

A: First of all, if you have the nozzles kit, install the washer since this will stop the leakage of water flow in the middle chamber and reduce the flow on the base plate. This alone will often give you some improvement in temperature. As for which nozzle to get, it depends on each setup but there is a good guideline agreed by the experts : For dual-cores, if you have a very strong pump like a Iwaki and CPU-only loop, the 3.5mm or 4.5mm nozzle is the best way to go. For a normal loop with a DDC or D5 and possibly more than the CPU in a loop, a 5.5mm nozzle is a better choice but if it is very restrictive due to the rest, get the largest (6.5mm). However, if you own a quad core, it's almost a given to get a quad nozzle (the one with a split in the middle) for the best performance but make sure the orientation it correct (the cores is across the IHS with the markings on the bottom when you look toward the cpu).

However, if you have the Fuzion CPU v2 (released to market recently), they don't use nozzles but they have a quad-core mid-plate available for those running a Intel quad-core. This new version is slighty more restrictive but that's more due to a design fix of the v1 mid-chamber leakage issue. The performance is slighty better with the design fix as well.

Q: I heard the Fuzion block is very restrictive, is that true?

A: Before answering this question, D-Tek made 2 blocks called the same, a Fuzion CPU block and a Fuzion GPU block. When we look at the CPU version, it's the most free-flowing block we can get and it get restrictive only if you get a nozzle in it (it get more restrictive with smaller nozzles as outlined above). With a quad nozzle, it's still very free flowing. The GPU version (the one you put on video cards) is the most restrictive block in the market and that's why lots of people get confused about the restriction level. That's also why lots of people will recommend getting a dedicated loop just for the Fuzion GPU or get very strong pumps like Iwakis.

Now, it's becoming a moot point because D-Tek released a new v2 of the GPU block, a lot less restrictive than v1 and working great.

Q: I'm interested in the EK supreme block, is it restrictive?

A: If we compare to the curren crowd of waterblocks, it's indeed much more restrictive so it's better to use it alone in his own loop or to use either 2 pumps in series or a Iwaki pump. However, with the restriction also come good performance on large dies. In the end, it's a good pick with the Fuzion but the final decision is determined by the amount of restriction you can live with and the number of blocks in a loop.

Xilikon · Jul 29, 2008

Updated the FAQ with the latest informations and market changes.

Got questions on watercooling? Official WC FAQ

Xilikon

[H]ard|DCer of the Year 2008

Xilikon

[H]ard|DCer of the Year 2008

Xilikon

[H]ard|DCer of the Year 2008

Xilikon

[H]ard|DCer of the Year 2008