Under which condition should push joints not be used?

Push joints are specifically designed for connecting pipes in a way that allows for flexibility and ease of installation. However, they have limitations when it comes to how the pipe is aligned during installation. When a pipe is pushed on at an angle, it can cause an uneven distribution of forces on the joint, leading to potential failure or leakage. Angled connections can compromise the integrity of the push joint, resulting in improper sealing and a higher likelihood of separation over time.

In contrast, the other conditions mentioned, such as the material of the pipe (copper), the diameter of the pipe, and the need for insulation, do not inherently affect the functionality of push joints. Therefore, maintaining proper alignment is crucial to ensure that push joints perform effectively and maintain a secure connection.