How do John Guest Fittings Work?

How John Guest fittings work

What are John Guest Fittings

John Guest fittings are commonly known as "Quick Connect" fittings due to their innovative design that enables fast and effortless installation. These fittings allow users to connect tubing or hose securely without the need for tools or additional clamps. By simply pushing the tubing into the fitting, it locks in place, providing a reliable seal. Most of the RO filter systems we sell use John Guest fittings. These quick-connect fittings make it easy to connect a reverse osmosis filter system with an RO faucet or refrigerator water dispenser. 

How to Connect and Disconnect John Guest Fittings

This video shows how easy it is to connect and disconnect John Guest fittings

To Connect a John Guest Fitting

Cut the tube square and remove any burrs or score marks. We recommend using a tube insert for soft or thin-walled plastic tubing.

Make sure that the hose or tubing intended for insertion into the John Guest fitting is cut straight. Improperly cut tubing can impede a secure connection.

Push the tube into the fitting and up to the tube stop

Insert the tubing or hose into the John Guest fitting. Upon encountering slight resistance, apply additional pressure, allowing the hose to advance a couple more millimeters into the fitting.

Pull on the tube to check that it is secure. Test the system before use.

Next, gently pull the hose outward to verify that the connection is firmly secured. If you have a leak once the water is turned on, it is most likely because you haven't pushed the hose in far enough.

To Disconnect a John Guest Fitting

Make sure that the system is depressurized, then push the collet square against the fitting. With the collet held in this position, the tube can be removed

Before disconnecting, first make sure that the system is depressurized. Locate the small circular ring, known as the collet, at the fitting's end. Push the collet away from the hose (toward the fitting) while simultaneously pulling on the hose. Using a Pi-Tool can facilitate easier disonnection, as it helps to engage the collet to release the hose.

Expert Tip

John Guest Fitting Sizes

This can be confusing to customers because when a fitting refers to 1/4 or 3/8, it’s referring to the outside diameter (OD) of the tubing size that connects to the fitting, not necessarily the diameter of the threaded or quick-connect opening.

What Types of John Guest Fitting Types are Available?

There are a few different JG fitting types available:

    • Female thread fittings
    • Stems (or male fittings) threaded on one end with quick connect on the other end
    • Elbow quick-connect fitting

John Guest fittings can be built into the filter or can be a separate fitting that attaches to a filter with female threads on one end and John Guest quick-connect fitting on the other.

For example, this filter is available with different fittings on the same filter:

Helpful John Guest Parts

Recommended John Guest tools to have on hand:

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Optional John Guest Release Tool for Quick-Connect Collet
  • This "PI-Tool" works for both 1/4" and 3/8" John Guest collets.

  • Helps to more easily release the tubing of fittings or valves and the secure John Guest collet.

  • Tool is not required to release quick-connect fittings, but makes it easier.

  • Ensures gentle and precise disconnection, reducing the risk of damaging the tubing during removal.

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Optional John Guest Locking Clip
  • John Guest 1/4 or 3/8" Locking Clip ensures a secure connection.
  • Attaches a tube to the neck of a push-to-connect fitting to prevent collar release from engaging and accidently loosening.
  • Enhances the ease of releasing tubing when needed by providing a convenient mechanism for securely locking and unlocking the tubing without requiring manual force.
  • Tube fitting locking clip works on nylon and polyurethane tube fittings.
  • Working pressure up to 150 psi.

What is a Push-Fit Fitting?

John Guest push-fit fittings are a type of quick-connect plumbing fitting commonly used in water filtration systems. These fittings are known for their ease of installation (decreasing installation time by as much as 40%) without the need for tools or additional equipment. And without the need for tools, this allows easier installation of water filtration equipment in small, confined spaces, such as under a kitchen sink.  

Why are John Guest Connections Commonly Used in reverse osmosis (RO) Systems?

Below are a few reasons why John Guest fittings are commonly used with reverse osmosis drinking water systems:

 1. Quick and Easy Installation:  John Guest fittings are designed for quick and easy installation without the need for specialized tools. They use a push-fit mechanism, allowing users to connect tubing without the hassle of traditional fittings that require compression or threaded connections. This can save time and labor during the installation process. 

2. Reliability:   John Guest fittings are known for their reliability. The push-fit design create a secure and leak-free connection when installed properly. This reliability is crucial in RO systems, where any leaks or loose connections could lead to wasted water or even water damage in the home. 

3. Versatility:  John Guest fittings are versatile and can be used with various types of tubing, including plastic and flexible tubing commonly used in RO systems. Fittings come in different sizes to accommodate different tubing dimensions, providing flexibility in system design. 

4. Removability and Reusability:  These fittings allow for easy disconnection and reconnection without damaging the tubing. This feature is valuable during maintenance or system upgrades, as components can be easily removed and replaced without the need for cutting or re-joining tubing. 

5. No Special Tools Required:  Unlike some traditional fittings that may require special tools for installation, John Guest connections can be assembled without the need for tools. This simplicity can be advantageous in various settings, especially for DIY installations or situations where access to tools may be limited.   

6. Reduced Risk of Contamination: The push-fit design minimizes the risk of contamination because there are no threads or compression sleeves that could trap debris or promote bacterial growth. This is important in RO systems where maintaining water purity is a critical concern. 

 7. Cost-Effective:  While the initial cost of John Guest fittings might be slightly higher than some traditional fittings, the ease of installation and potential labor savings can make them cost-effective in the long run.  

John Guest Fittings Frequently Asked Questions

Do John Guest fittings leak?

John Guest fittings are renowned for their reliability and efficiency, typically offering leak-free performance when installed correctly. However, like any plumbing or fluid system component, leaks can occur if the fittings are not properly installed, if the tubing is damaged or improperly cut, or if there is excessive pressure or stress on the connection. Ensuring that the tubing is cut cleanly, inserted fully into the fitting, and that the fitting is compatible with the tubing size are essential steps to prevent leaks. Additionally, regular maintenance and inspection can help identify and address any potential issues before they escalate. Overall, when installed and maintained properly, John Guest fittings are known for their minimal risk of leakage.

Why are they called John Guest Fittings?

John Guest fittings derive their name from John Guest Ltd., the pioneering British company that introduced and popularized them. Established by John Guest in the 1960s, the company revolutionized plumbing and fluid systems with their innovative quick-connect fittings. Renowned for their quality and reliability, these fittings quickly became synonymous with the company's name. As a result, they are commonly known as John Guest fittings, honoring both their origin and the company's role in their creation.

Can I Reuse John Guest Fittings?

Yes, John Guest fittings can easily be disassembled and reused, provided they are in good condition, properly cleaned, and the same type and size of tubing is used during reassembly.

What are John Guest fittings?

John Guest fittings are quick-connect fittings widely used in plumbing and fluid systems. Known for their ease of installation, these fittings allow tubing to be securely connected without the need for tools or additional components. They feature a push-fit design, where tubing is simply pushed into the fitting to create a tight seal. This makes them ideal for water filtration systems, including reverse osmosis units.

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