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Old 03-09-2006, 04:24 AM
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Default Water Cooling Low Down


Alot of people want to get the max out of their computer. Most people know that cooling is very important, especially when running overclocked hardware. So I'm going to give you a run down on water cooling your PC. Its not as hard, or dangerous as many people believe. As the whole system is sealed, no liquid will EVER get near your pride and joy components. There's no water sloshing round the CPU. There's no water sloshing round the PSU. There's no need to worry Just a quick word of warning though, always test the water cooling system in the case, fully setup, without having power to any other components (mobo etc) because if you DO have a leak, then you will deffo fry everything the liquid comes into contact with. If you test the cooling system before you power up the rest of your rig, and it leaks, then just dry out your components properly, fix the leak and try again.

If used and assembled properly, a water cooled system will be the most efficient cooling system performance-wise, in addition to allowing faster overclocking. And it looks cool too

Basics: Any PC water cooling system needs at least three components to work. A pump, a radiator and a waterblock. The liquid forms a loop, starting at the pump, travelling along to the radiator, where the water is cooled, and passing through the block. The block is connected to the CPU and transfers heat to the water, which then goes back to the pump and the cycle starts again.

Basic Water Cooling Layout

You should never mix copper and aluminium in a water cooled system if you can help it as when these metals are placed together in the same body of water, rust will occur very quickly and your water cooling system will not work as well. Try and use a copper radiator and water block, or aluminum radiator and water block, not one copper and one aluminium. If you cannot help it, then use an anti-oxidant in the water.

Condensation can occur in a water cooled system and you should be aware of it. However this will only happen on the radiator if the water temperature drops below the air temperature in the room and so happens very rarely. Condensation is more of a risk if a chiller is used in the water cooling system (Chillers are talked about near the bottom of this post)

Never use tap water in your cooling system. If you do you will have rust all over it within a week. Plus you will get all sorts of gunky build ups in the pump. Only used distilled water. You should also add coolant additive, this will keep the system free from any build ups for at least six months. After that time, strip down the system and clean all the parts in alcohol.

You will need a fan connected to your radiator (much like on a car) to cool the water in the radiator. Normally 1x120mm fan is enough, so water cooled PC tend to be very quiet. 80-120 CFM (Cubic Feet per Minute) should be more than enough to keep any radiator cool.

The pump is basically the same kind of pump used in a fish tank. The pump needs to be powerful enough to pump the water up to the highest point of the system without any problems. A 12V pump can be connected directly to the computers PSU. A 240V / 110V pump will obviously need to have a cable running out of your machine.
There are two main types of pump:

Inline Pumps: These are pumps that have an inlet and an outlet, and using this kind of pump will not require you to have a water reservoir. These pumps will usually produce some slightly cooler temperatures, but are harder to connect and bleed. (Bleeding refers to the process of removing air bubbles inside the components/tubing)

Submersible Pumps: These are the kind of pumps which you can find in your fish tank. They must be submerged completely in water to work, therefore you will need to add a reservoir to the case. Usually submersible pumps are sold in conjunction with a reservoir, and can also be called reset-pumps. These pumps are much easier to fill and bleed than inline pumps.

The radiators function is simply to cool down the water which was heated up while going through the waterblock. The higher a radiator is rated in BTU (British Thermal Unit), the more heat it is capable of dissipating. For example a radiator rated for 3000 BTU could cool down about 810 watts of heat per hour, equal of about 10 computers worth. Some radiators are produced in professional machine shops explicitly for computer cooling such as's Black Ice radiators.

The most important part of any system is the waterblock. Since this is the only part of the whole system, which is actually touching the processor, it must conduct heat as well as possible. There are two things to look at when looking at the performance of a waterblock. First is the surface area. As much of the block as possible needs to touch the CPU for the water to actually grab some heat before it is expelled back into the pump. Always use a good quality heat transfer paste on your CPU, this is especially important in a water cooled system. The other thing to look at is the actual material it is made out of. Some waterblock manufacturers have even been making waterblocks out of silver to improve heat-transfer, since silver is one of the best heat conductors known.

Tubing is something that is often overlooked. A good choice of tubing will prevent a lot of problems with the installation. If for example there are a lot of tight corners inside your case, you might want to add a few 90* elbows, because thinner tubing will tend to kink and restrain flow when bent too much. On the other hand, thicker tubing will be harder to bend, and will often spring back into its original shape, causing un-needed pressure onto the water block. Also be sure to use tubing, which matches the outlets on your components. Most waterblocks, radiators and pumps use 3/8 or 1/2 inch ID (inside-diameter) barbs, but some manufacturers might use other sizes.

Now you know what you must have in your water cooling system, lets go through what you can add on to it.

Flow Meters
Flow meters are small devices, usually positioned inside a window, which gives vital information about the water cooling system. When water is passed through the tubing, it creates a certain pressure. When that particular pressure is exerted on the wheel or fan located inside the flow meter, it will cause the device to spin, revealing to the owner that the system is operating properly. Slow spinning or stopping of the flow meter will indicate that either the pump has failed, or the system is leaking.

Temperature Sensors
Temperature Sensors used in water cooling are just like the one under your processor, or the ones that come with a Digital Doc. The only difference is that it has to be electrically insulated, and must not affect water flow, not cause any leaks. In order for this to happen the sensor is normally coated in silicone and only the tip is pushed through the tubing and touching the water.

Chillers are mainly used in server type cases or buy people who have a large custom case, as they take up a lot of room. They require two loops of water, or two radiators. Chillers are expensive and take a long time to cool down enough to work well, so I won't say anymore about them as for a standard PC they're not very practical.

Obviously a major part of water cooling your case is that it looks cool! Most of the parts mentioned above can be bought in clear or UV reactive cases. The coolant additive can also be bought with a UV reactive agent, with no ill effects to the cooling power of the system.

I hope that this post has helped you to realise whats needed in a water cooling system and dispelled a few myths about the dangers of the dreaded H2O

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