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.
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.
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.
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.
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.
The fitting can be used again without the need for replacement parts. (Ensure the fitting is clean before every use).
Remember to pressure test the completed installation according to the recommendations in the John Guest Technical Checklist.