How do the John Guest fittings work?

To make a connection, the tube is pushed in by hand. The unique patented John Guest collet locking system holds the tube firmly in place without deforming it or restricting flow.

1. Cut the tube square
   Cut the tube square. It is essential that the outside diameter be free of score marks and that burrs and sharp edges be removed before inserting into the fitting. For soft, thin-walled tubing, we recommend using a tube insert.
2. Insert the tube
   Fitting grips before it seals. Ensure the tube is pushed into the tube stop.
3. Push up the tube stop
   Push the tube into the fitting to the tube stop. The collet (gripper) has stainless steel teeth that hold the tube firmly in position, while the O-ring provides a leakproof seal.
4. Pull to check and make sure the connection is secure
   It is a good practice to test the system before leaving the site or before use.

Disconnecting

Push in the collet and remove the tube.

To disconnect, ensure the system is depressurized before removing the tube. Push in the collet squarely against the face of the fitting. With the collet held in this position, the tube can be removed. The fitting can then be re-used.

John Guest Fittings and valves can be used on the following types of tubing.

Plastic Tubes – polyethylene, nylon, and polyurethane conforming to the tolerance shown below. For soft or thin-walled tubes, we recommend the use of tube inserts.

Braided hose – Use the Tube to Hose Stems when using a braided tube or hose. Use of clamps to retain braided tube on barbs is recommended.

Metal tube (soft) – brass, copper, or mild steel conforming to the following tolerances. Hard metal tubes are not recommended with these fittings.