How to Use Twist Lock Fittings

Making a Good Connection

John Guest Twist and Lock Diagram 1

Like John Guest Standard Fittings, Twist and Lock Fittings have a collet with stainless steel teeth that grip the pipe when fully inserted, and an O-ring to provide a permanent leak-proof seal. The additional benefit of the Twist and Lock fitting is that a twist of the screw-cap gives greater compression on the O-ring seal and locks the pipe in place for greater security.

Step 1 – Prepare the Pipe

John Guest Twist and Lock Diagram 2

To prevent damage to the O-ring remove all burrs and sharp edges. When using Speedfit Pipe, we recommend the use of a Pipe Insert. The insert should only be used with Speedfit Pipe.

Step 3 – Push Up to Tube Stop

John Guest Twist and Lock Diagram 3

The fitting should be in the ‘unlocked’ position. This is shown by a small gap between the screw-cap and the body flange. Push the pipe into the fitting and up to the pipe stop.

Step 4 – Pull To Check if Secure

John Guest Twist and Lock Diagram 4

Twist the screw-cap until it touches the body flange. This locks the pipe into position and increases the o-ring seal around the pipe.

Pull to check that it is secure. It is good practice to test the system prior to leaving the site or before use. The recommended test procedure is shown in the John Guest Technical Checklist.


Ensure that the system is depressurized.

John Guest Twist and Lock Diagram 5

Be sure to twist the screw-cap back to the unlock position. Push the collet square against the face of the fitting by using fingers. With the collet held in this position the pipe can be removed.

John Guest Twist and Lock Diagram 6

The fitting can be used again without the need for replacement parts. (Ensure the fitting is clean before every use).

What Not To Do

  • Do not use damaged or scored pipe.
  • Do not use a hacksaw to cut the pipe.
  • Do not leave burrs on the end of the pipe.
  • Do not forget to push the pipe fully into the fitting, past both the collet (gripper) and the O-ring.
  • Do not insert fingers into the fitting as the stainless steel teeth may cause injury.

Remember to pressure test the completed installation according to the recommendations in the John Guest Technical Checklist.