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The big watecooling FAQ


1. Introduction

On the following pages we want to give answer to the most common questions encountered by our users. This FAQ is for both beginners and more experienced users as it gives interesting hints and advice. The FAQ will be updated from time to time as improvements will emerge. Especially on the field of pumps and waterblocks progress is constantly made.

Should you have any notes regarding the FAQ (e.g. mistakes, missing information, outdated data etc. ) Please contact us at


2. How does watercooling work?

Watercooling a PC is very similar to watercooling a car (having been an inspiration to watercooling a Computer) and has the very same effect as in a car: lower temperatures.

A watercooling system works roughly as follows and consists of the following components:
The pump pumps the cooling liquid through the PC to the waterblock: This or these cool the chips to be cooled and then the water continues on to the radiator, which cools the water (with the help of fans) down and is for that reason called heat exchanger. The reservoir equalizes the expanding water in the system to avoid overpressure and development of air bubbles. (Recurring questions)


3. Why watercooling and who can profit from it?

Watercooling is not just for people who just want to have a cool system or ones who have temperature issues, but also for Hardcore Overclockers and people who want to have an extremely silent system. And additionally watercooling looks extravagant and is therefore often used for modding purposes.

But beware:
Watercooling is not for the common user, as it can be very elaborate to install a watercooling system and to put it into operation. Technical aptitude and some PC know-how and experience should be existent. The comparatively high costs in relation to other cooling systems should also be considered. 


4. Water and electronics, does that match?

If good components are used and everything is installed properly everything should sealed tight and work smoothly. During installation the system does not carry any current and if the pump should fail the waterblock is capable of cooling the system onward for a short while. Screw-in fittings should be referred over plug-in connectors, especially if the system is transported more often. Additionally system should be checked to be in working order before power-up. But normally watercooling is not less safe than any fan, as it can fail as well.

But beware: For watercooling applies: "Who buys cheaply will buy twice or at best not at all!"


5. What do i need for a watercooling system?

In this part all components will be explained and a short recommendation of products will be given.


5.1. Pumps:

The pump is responsible for ''transporting´'' the water through the system. We generally recommend a 12V DC pump as such a pump avoids having possibly dangerously high voltages in the system and the pump can be attached to the PCs power supply and will therefore be started together wih the PC and does not have to switched on separately. The myth that a strong pump will always give the lowest possible temperatures is wrong though, as in a watercooling the whole composition  matters most. But the pump should not be too weak, as a large systems may potentially not be supplied with enough pressure to fully play out its potential.

The information about a pump that most attention should be given to is not the maximum amount of flow, but rather the maximum pressure head, as it gives a clue about the pressure the pump is capable of building up. We recommend to not save on the pump as a good pump allows almost unlimited extension of the system in future. Any pump, no matter how quiet-running should be decoupled, as all pumps cause vibration. ready-made insulation boxes or decoupling sets can be purchased, but a piece of foamed plastic is usually sufficient as well.


    Laing DDC-Pump - 12V Pro

      The Laing is produced by a company specialized on production of pumps for industrial applications. Its main features are the small size and its strength, but it is also very noisy with its standard cover. The standard cover should be replaced by a different (plexi)cover. By doing so the pump works more efficient and is also a lot less noisy. But still the HPPS+ is even decoupled even more quiet ( usually inaudible)
      The Laing can easily be mounted in a 3,5'' bay and is then additionally decoupled. The pump is also often used for modding due to its design, and as it can be easily lit up.
      By some simple soldering on the pump's PCB the Laing Pro can be modded into a Laing Ultra, but this results in a loss of warranty and it will be more noisy, but also definitely stronger.

      Technical data:
      • Measurements: (WxDxH) 62x62x38mm (Without fittings)
      • Measurements Plexi cover: 80x80x25mm (Without fittings)
      • Motor design: electronically commutated ball motor
      • Nominal voltage:: 12 V DC 
      • Pressure head: 3,7m
      • Max. flow rate: 420l/h


      Two fittings total are required, the named fittings can be combined.

      The Laing should be decoupled by one of the following means:

      Additionally a lubricating Water additive should be used.
      Here a modification to get a better performance out of your pump.


    HPPS Plus - 12V Pump

      The HPPS+ is an enhanced Version of the Eheim 1046. Innovatek is a renowned manufacturer of watercooling components. The HPPS+ features extremely quiet operation and very low power consumption. An integrated microprocessor allows the choice between three modes of operation: 

      • Silent (1,65m pressure head, inaudible).
      • Normal (factory configuration 2,05m pressure head, quiet)
      • Power (4m power head, audible).
      • Auto (pump determines itself how much power is needed).

      Here you find instructions on how to switch between the 4 modes via soldering

      Technical data:

      • Measurements: (DxWxH)130 x 55 x 65 mm (Without fittings)
      • Motor design: radial pump with full ceramic bearing (special shaft rotor bearing) 
      • Nominal Voltage: 12 V DC 


        • Included

5.6. Hard disks

Hard disk coolers usually consist of one or two metal plates in which channels are machined. Through these the water then flows with little flow resistance.
For installation of a hard drive cooler a 5,25'' slot should be available, as the HDD should be cooled at its sides.
A hard drive does not necessarily require cooling if it does not run too hot or is too noisy.
Most coolers decouple and insulate the HDD additionally.



5.7. RAM coolers

If there is only bad airflow in the case or extreme OC is applied, one can thinka bout watercooling the RAM as well. Normally though, the RAM is, just like the power supply, one of the components that can easily be cooled with one or two case fans.



5.8.  Watercooled power supplies:

Watercooling the power supply is usually not advisable, as watercooled power supplies emit massive amounts of heat and unnecessarily heat up the water. In addition to that, such power supplies are very expensive.



5.9. Radiators

The radiator, also called heat exchanger, is responsible for transmitting the heat absorbed into the water by the coolers into the air. The water temperature can only be cooled down to room temperature, but never go below it. In short: Room temperature is the lowest possibly achievable water temperature by a radiator.

That leads to the problem -just as with air cooling- in summer normally higher (water)temperatures are reached, as the room temperature is higher. The more components are included in the watercooling system, the more powerful the radiator should be as more heat is transmitted into the water. If a radiator is suitable for a system can be determined by measuring the water temperature.

Generally it can also be said, that the thicker and bigger  radiator, the better its cooling capabilities. Usually thicker radiators require stronger fans though, as more power is needed to overcome the air resistance. Also the fin spacing should be considered, as the the closer the fins are placed together, the stronger the fans used should be. 

Another important aspect is that radiators need air to ''breathe'' , it should have at least 5cm space for air intake and dissipation, as otherwise potential hotspots may develop.

Both actively and passively cooled radiators are available: Actively cooled ones are usually smaller and more powerful, passively cooled ones are fanless and therefore (almost) inaudible radiators. The larger its surface, the more powerful a radiator. passively radiators are usually much more expensive than actively cooled ones.

We recommended only radiators for 120mm fans, as the smaller models are not as priceworthy. There are  four kinds of actively cooled radiators:

    • Single radiators (radiator for one 120mm fan)
    • Dual radiators (radiator for two 120mm fans)
    • Triple radiators (radiator for three 120mm fans)
    • Quad- and larger radiators (radiator for four or more 120mm fans)

There are different faceplates for all common sizes! Warning: Not every faceplate fits on every radiator.

Passive radiators are significantly larger than active ones to achieve the same cooling capability. Just as for active radiators the rule ''the bigger, the better the cooling performance'' applies.

Every passive radiator can be used actively by the use of a fan, e.g. the Mora can be used without fans, but a radiator designed for active cooling should be used as such.


5.10. Fans

Fans are put on the radiator in active systems. Depending on how quiet the system is supposed to be the fans vary. We recommend the ''Scythe S-FLEX 120mm“ from 800 over 1200 up to 1600 rotations/minute. Naturally the loudness but also the flow increases with the speed of a fan. For a Silent-system the 800 rpm version should be used.

A lower-priced alternative are the Yate Loon D12SL-12, which also deliver very good results.
further recommendations are: Noiseblocker Blacksilent XL1, Noctua NF-P12 and Nanoxia FX12, which are also especially quiet and can produce great flow.
It is recommended to decouple the fans with special decoupling kits.


5.11. Reservoirs:

The reservoir is equalizes the expanding liquid to avoid over- or underpressure. It also serves to ''catch'' air bubbles, especially after filling the system.
Also the system is filled with water via the reservoir.
Theoretically the reservoir is not needed, but for that the system must be perfectly full and without bubbles, but this state is very hard to achieve and impractical.

A reservoir should not be too small, as otherwise bubbles may develop and the system would have to be refilled more often. A capacity of around 250ml has proven ideal.

A reservoir should at first fulfill it purpose, but can also be an optical highlight of the system, e.g. if lit by LEDs or with the help of coloured coolants.

A little piece of advice: It can happen that a reservoir leaks in the beginning, as screwing on the cover produces an overpressure that wants to come our. This can be avoided or reduced by screwing on the cover very slowly.

Lighting module

There are three options of how to integrate the reservoir into the system: 
    • The water flows directly through the reservoir to the components. This is the most common type of installation.

    • The reservoir is directly integrated into the pump (e.g. in a Laing, which can lead to air bubbles and is therefore not recommended), it therefore is an indirect component of the system.

    • The water does not run through the reservoir directly, but is integrated over an T-fitting into the loop and if any pressure builds the water flows into or from the reservoir into the loop. Therefore the reservoir is an indirect component of the cooling loop.

Here a Recommendation:


5.12.  Fittings:

The fittings allow connecting the different parts of a watercooling system with tubing

Screw-in fittings are to be preferred over plug-in fittings, especially if the PC is moved often. There are different tubing sizes, but only three have become popular. For a watercooling system one kind should be chosen and not be mixed with other sizes.

Standard sizes are:
    • 10/8mm (8x1)
    • 8/6mm (6x1)
    • 11/8mm
Angled fittings reduce flow, but this can be equalized by a strong pump. Angled and straight fittings can be mixed freely and the one should not hesitate to use angled fittings, as they have great advantages but only few disadvantages.

If tight radiuses are made with the tubing anti-kink springs should be used.

Always note what kind of threads the wanted waterblock has and what size of tubing is wanted.


    • 1/2“ not very common
    • 1/4“ the standard
    • 1/8“ used almost only by Aquacomputer
Example: If the waterblock has 1/4'' threads and tubing with a diameter of 10/8 is wanted, the following fitting is the right choice.
Here an extensive choice of fittings.

Alls companies comply to these standards except Thermaltake. This company uses american connectors and generally has very poor quality. For these reasons we do not recommend Thermaltake.

Almost no waterblocks have fittings included, they almost always have to be bought separately.


5.13. Tubing

The tubing channels the water from component to component. The sizes of tubing are already fixed by the fittings (see above).
    • PUR is a little stiff
    • PVC is flexible (our recommendation)
    • Tygon is very flexible but also expensive

The more flexible the tubing the less nerves and strength are needed for installation and the risk of kinking the tubing is reduced. During installation special attention should be be given to not kinking the tubing, as blockages could develop and flow be reduced massively. Stiff tubing is hard to bend but does not have the problem of easily buckling, flexible tubing has the exact opposite properties.

Throughout the system only one size of tubing and fitting should be used to avoid having additional flow resistance

Our Recommendation: Screw-in fittings 10/8mm with PVC tubing10/8mm.

5.14. Anticorrosive

Only distilled water with anticorrosive or ready-made coolant mixtures should be used.

UV additives are not recommended, as they may lead to algae forming. Additionally UV colouring is toxic and may sediment in the loop.

Without suitable anticorrosive the waterblocks corrosion will occur very quickly and additionally algae or small particles may form which will clog the waterblocks.
For a Laing pump a lubricating additive should be used. 

Recommendation: Here a very good ready-made Coolant or a  concentrate for mixing with distilled water.


5.15. Tower

The choice of  a tower is always a question of personal preference.

For internal watercooling a big tower or a very spacious midi tower is recommended. If internal space is not sufficient, it is no problem to mount the reservoir and/or the radiator on top of the case.

Here a few mounting kits respectively faceplates.

For an external watercooling system almost every tower can be used. Aquatuning also offers the service to machine the hole for the radiator.

Here a few towers in which a radiator can be fitted without sawing and extensive drilling.

Single radiators fit in almost any tower.

Dual radiators:
Two dual radiators:

Triple radiators and bigger:

Please not the exact tower name, as the links are set at categories, as the towers are often available in different colours and versions.


5.16. Maintenance and monitoring

A watercooling system, once up and running properly, needs no more care or time than an air cooling system. All that is left to do is sometimes refill water lost by diffusion and sometimes cleaning fans and the radiator from dust.
The Coolant should be changed every 6 month to make sure that no algae developed and the mixture of anticorrosive and water is still right. To empty the system just put a container under the tubing and remove it from the fitting.


6. Active or passive cooling?

If active (with additional fans) or passive (without additional fans) cooling is used is a question of available space and noise level of the system. An actively cooled system needs less space due to its smaller radiator but is more noisy because of the used fans. The exact opposite is the case with passive cooling, as there the radiator is bigger in order to be able to dissipate the heat without fans, but it is also inaudible.
Active cooling is better for overclocking.

The question that has to be asked, if one wants to overclock or have an absolutely silent system with limited overclocking capabilities.

A passively cooled system is significantly more expensive and
usually runs hotter than an actively cooled one.
It basically is a question of space and money.


7. Internally or externally?

If internal (inside or at the case) or externally (radiator, fans and pump separated from the case) is again a question of space, this time inside of the case, and the available financial budget.

An internal system needs less space in total, but does require a large case. It is usually cheaper.

An external system needs more space, but does not limit the choice of towers. It is usually more expensive.

Cooling capabilities achieved can be both the same. It very much depends on the choice of tower and the finances on how to decide.

Here a few good external systems:

We recommend these quick coupling kits.


8. Ready-made system or self-construction?

Ready-made systems almost always have a weak point. A weak pump, too small of a radiator or just plain too expensive are the most common things. In any case self-construction is the best choice. If any questions turn up the members of our forum will be happy to help.


9. In what order?

There is no special or best order of waterblocks in a cooling loop. The temperature differences in the loop are at maximum a few degrees so there is no ''warm'' and ''cold'' water in the system therefore making the order of waterblocks irrelevant for their cooling performance. The best order is the one in which least tubing is needed. Only the reservoir should always be directly before the pump in the loop.

Separating a single cooling loop should be avoided in any case, the worst case scenario is that there will be almost no flow through one of the branches.


10. Monitoring tools and lighting

Here we shortly give an overview of what can be used for monitoring of a watercooling system and what helps to always have control of the system.


10.1. Temperature monitoring

This is probably the most useful accessory for a watercooling system. If there is no control unit or fan controller with a temperature monitoring function in the system a temperature sensor with display should be used. As temperature sensors we recommend inline designs as with them no additional fittings have to be purchased or a simple temperature sensor with display that can be mounted in a free reservoir connector.

Temperature sensors with display:

For fans and control units:


10.2. Flow meter

A Flow meter is an important accessory which can be used optionally. Flow meters with low flow resistance should be preferred. If a control unit is already in the system the flow meter should be supported.
There are no precise values on how high flow should be, but it can generally be said that a flow of 40-50l/h is sufficient. Everything below 30l/h is too low; Everything above 60l/h is very good.


10.3. Fan controller

If the user wants to comfortably adjust fan speeds we recommend using a fan controller. Fan controllers with display can also often be equipped with temperature sensors. We especially recommend Zalman and Scythe.


10.4. Control units

The control unit can be used for just about anything in monitoring a watercooling system. They are designed especially for watercooling systems and everything from flow to fan speeds can be monitored and adjusted.


10.5. Lighting modules and LEDs

For all users that wish to set the stage for their watercooling system LEDs are a good choice. Some waterblocks already have pre-drilled holes for LEDs. The most popular method is to light the Reservoir. For doing so a lighting module and a fitting LED is required, as well as a free connector at the reservoir.


11. Initial operation

Take distilled water and flush the radiator and waterblocks thoroughly. Repeat the procedure multiple times and let everything dry off.

After that install all the hardware with all the waterblocks. Check the tubing for buckles; tighten the fittings well, but only by hand , never use a wrench or other tools. Now fill the system by pouring water into the Reservoir and switching on the pump by one of the following means:

Either take an old PC and connect the pump to it or bridge the power supply.
Never swith on the PC if the system was not checked for leakage. Additionally all air bubbles should be out of the system. In order to do so, move the radiator in all directions. After everything is sealed tight and no more air bubbles are in the system we recommend to let the watercooling loop run for another one or two hours on its own for testing.

If any hardware got wet, remove the component and let it dry well over night and install it again the next day. Then repeat the procedure described above. The hardware should normally not be damaged if it was not connected to any current.


12. Recurring questions

Copper and aluminum in one loop. Is that good?
    If a good anticorrosive there should be no problems. If none is used the aluminum will dissolve slowly.

My system is running hot, do i need watercooling?
    Such problems can normally be resolved with a good air cooling system as well.

Is this Thermaltake watercooling system good?
    >From or point of view Thermaltake usually makes watercooling systems that are noisy, cool poorly and are not expandable well. Additionally the uncommon american tubing standards are used.

How much does a good watercooling system for my CPU cost?
    If one wants a watercooling system we recommend to not use cheap ready-made kits, as they usually are not much better than a high-end aircooler. A good kit costs roughly around 200€.


13. Assembly and integration into the tower

Since it does not help much to just explain the assembly of a watercooling system, we decided to make a video that shows everything that a user needs to know.

To the video


13.1. Right and wrong


The tubing should not be cut this way, as it may lead to leakage in the system.

This is the right way:

Because then it looks like this:


14. Compilations:

To give our readers guidance, we compiled products which give best value for money in three price categories.


14.1. Introduction:

All Systems were compiled for Intel socket 775. Alls systems are designed for best expandability, which is the reason why only triple radiators are used. The reservoir is, except for the low end compilation, only a suggestion by us. We listed 3 products at most. Radiator mounting kits radiator faceplates, temperature monitoring, control units and fan controllers, anti-kinking springs, flow meters, lighting modules, LEDs etc. are optional.

bold: preferred choice
standard: alternative choice


14.2. Low-End (approx. 180€)


14.3. Midrange (approx. 260€)


14.4. High-End (approx. 390€)


14.5. Passive cooling (approx. 400€)

CPU block: Alphacool NexXxoS X2
Enzotech Water Block SCW-1
Aquacomputer cuplex XT di
Radiator: Innovatek Konvekt-O-Matic ULTRA (sufficient for heat dissipation of up to approx. 250W)
Cape Cora Pro 1042 Konvekt Ultra silber (sufficient for heat dissipation of up to approx. 225W)
Pump: Aquacomputer Aquastream XT standard
An upgrade to the Ultra version is possible at any time
Laing DDC-Pumpe 12V
Reservoir: EK Water Blocks Multioption RES 250
Innovatek Fass-O-Matic
Fittings: 10/8mm G1/4 fitting kit
Inlet adaptor G1/4 only needed with the Aquastream pump
Outlet adaptor to G1/4 only needed with the Aquastream pump
Tubing: 3* 10/8mm PVC Innovatek tubing
3* 10/8mm PVC tubing
Water additive: 2* Innovatek Protect ready-made 1000ml


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