How to Choose the Best PC Water Cooler Fitting for Your System

Posted by
Cameron Wise on December 09, 2022

Liquid coolers in personal computer and server applications require a water-tight seal to protect hardware from damage while maintaining the low temperatures that water cooling provides. This seal is created by fittings in areas where tubing connects to other tubing, pumps, and radiators. The market for water cooler fittings can be overwhelming because of the abundance of fitting types and sizes. However, understanding the components of your system can help filter out the fittings that work for your system and those that do not. Below you can find information on the types of liquid cooler fittings and how to find the perfect fitting for your loop.

Types of PC water cooler fittings

Liquid cooler fittings come in three main types: barbed, compression, and push-in. Not all fittings are created equal, and PC builders should be wary of the tubing used in their system before purchasing appropriate fittings.

Barbed fittings

Barbed fittings are an affordable type of fitting that can only be used with soft tubing. These fittings are installed on the inside of the tubing and secured with a clamp around the tubing’s outer wall. The clamp creates a seal by compressing the tubing’s inner wall with the outer wall of the fitting. Barbed fittings cannot deal with the same levels of pressure that compression fittings can, and they are less reliable as a result.

Advantages of barbed fittings

  • Inexpensive
  • Easy to use

Disadvantages of barbed fittings

  • Less reliable seal than compression fittings
  • Can only be used with soft tubing

Compression fittings

Compression fittings use a locking collar that compresses on the outside of the tubing to create a watertight seal. These fittings have long been the standard for PC liquid cooling because they are more reliable and aesthetically pleasing than push-in and barbed fittings. On the flip side, they are more expensive than alternate fitting types.

Soft tubing compression fittings work differently from rigid compression fittings. Compression fittings used with soft tubing are essentially barbed fittings with a built-in clamp that is more reliable than those used for barbed fittings. Soft tube compression fittings use both the inside and outside of the tubing for compression, so both the inside and outside diameter measurements of the tubing and fittings must match. If the measurements are not perfect, the fitting will fail to create a watertight seal, and liquid will leak during operation.

Rigid tubing compression fittings use O-rings to create a seal. Because rigid tubing is firm by itself, fittings used with it do not need to be inserted inside the tubing. Rather, the tubing inserts into an O-ring inside the fitting, the locking collar fits around the tubing, and another O-ring slides onto the tubing beside the locking collar. The locking collar, similar to the clamp in soft tubing compression fittings, compresses the adjacent O-ring, creating a seal that prevents water from leaking.

Advantages of compression fittings

  • Reliable seal
  • Can be used with both soft and rigid tubing

Disadvantages of compression fittings

  • More expensive than barbed and push-in fittings
  • Require more space than push-in fittings

Push-in fittings

Push-in fittings are the simplest type of fitting for a rigid tubing PC water cooler. Their biggest advantage is the ability to fit into tight spaces that other fittings cannot. They do not contain a locking collar or threads. Rather, they utilize O-rings that create friction with the tubing, creating a water-tight seal. These are less expensive than compression fittings, but they also create a less reliable seal. Consequently, most PC builders utilize compression fittings for their rigid tubing needs.

Advantages of push-in fittings

  • Inexpensive
  • Use up less space than compression fittings

Disadvantages of push-in fittings

  • Less reliable than compression fittings
  • Can only be used with rigid tubing

closeup PC tubing

How to choose the best PC water cooler fittings

Consider the right fitting for your tubing type

Soft water cooler tubing, also called flexible tubing, is a cheap and beginner-friendly option for your cooling loop. It is easier to install, route, and cut than rigid tubing, but it kinks more easily and is not as aesthetically pleasing. Flexible tubing is also more susceptible to clouding than rigid tubing, especially with colored coolant. The cleaner the liquid you use inside your tubing, the less likely it will cloud.

Learn more: Using distilled water for PC liquid cooling

Rigid tubing, also known as hard tubing, is not friendly for beginners because it is difficult to manipulate. However, routes designed with rigid tubing can be manipulated with adapter fittings. These allow you to change the angle of the liquid without bending the tubing. Rigid water cooler tubing can be made from a number of materials, such as glass, acrylic, carbon, and polyethylene terephthalate glycol (PETG). Hard tubing adds the benefits of a cleaner design, no kinks, and reduced risk of cloudiness. On the contrary, firm tubing is more expensive and is more susceptible to breakage than flexible tubing.

The type of tubing used for your water cooler determines the type of fittings that can be installed. Soft tubing, for example, can be used in conjunction with both compression and barbed fittings. Rigid tubing, on the other hand, cannot make use of barbed fittings, so compression or push-in fittings must be used. While barbed fittings are more economical than compression fittings, many PC builders who utilize soft tubing prefer compression fittings because of their greater leak resistance. Soft tubing compression fittings and hard tubing compression fittings work differently, so ensure that the fittings you use with your system are designed to work with your tubing.

Measure the diameter of your tubing

The size of your fitting must perfectly match the tubing size, which can be measured by its inner diameter, outer diameter, and wall thickness.

  • The inner diameter (ID) of a piece of tubing is the distance between the inner walls of opposite sides. The most common ID sizes are 1/2”, 3/8”, and 7/16”.
  • The outer diameter (OD) of tubing is the measurement between the outer wall of the tube to the outer wall of the opposite side. Common OD sizes for PC tubing are 1/2”, 5/8”, and 3/4”.
  • The wall thickness of PC cooler tubing is the difference between the OD and the ID. There is no standardized wall thickness of cooler tubing, so it is not safe to assume a tubing’s OD from its ID or vice versa. The tubing material plays a large role in its thickness.

If the fitting does not perfectly match the tubing size, then the seal will not be watertight, and you risk water damage from shorting your system.

Select the right thread size

Thread size is an important measurement when purchasing fittings for your water-cooling system. For your fittings to be effective, their thread sizes must match. Thread types in threaded fittings must be compatible to form an effective seal, so ensure that the thread types in your fittings is identical. The three thread types are NPT, BSPT, and BSPP.

  • NPT (National Pipe Thread) threads are the most commonly used thread type in the United States. If you purchase a fitting in the United States, you can be fairly certain it utilizes NPT threads. NPT threads are tapered and form a tight, reliable seal.
  • BSPT (British Standard Pipe Thread) threads are common in Europe, Australia, China, Japan, and some Commonwealth countries. These, like NPT threads, are tapered and form a seal that is slightly less reliable than NPT threads.
  • BSPP (British Standard Parallel Pipe Thread) threads are also common in Europe, Australia, and some Commonwealth countries. Unlike the other two types, these threads are not tapered. The seal of BSPP threads is also less reliable than NPT threads.

Learn more: Pipe thread type and size

How long do PC water cooler fittings last?

The fittings for your PC water cooler should last the lifetime of your machine. If you use your machine for five years, there is a chance you will need to replace the O-rings on your compression fittings if they are the fittings you choose. When upgrading the components of your PC, you will need to replace the fittings regardless of whether you change your tubing type or not. Because fittings are vital in protecting your PC from water damage, reusing fittings in an upgraded machine is not recommended.



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