Automated pressure equalization above and below completion plug of gate valve cartridge or a completion plug of a line stop fitting

A method for equalizing pressure above and below a completion plug while the completion plug is being installed into a gate valve housing or a line stop fitting that is in communication with an opening in a sidewall of a pipe, the method comprising:

• providing a completion plug, the gate valve housing or the line stop fitting and an installation assembly comprising an insertion tool, the gate valve housing or line stop fitting comprising a distal end connected to a proximal end, the proximal end connected to the pipe around the opening in the pipe, and an interior surface defining an internal diameter of the gate valve housing or line stop fitting that is large enough to accommodate the completion plug except at a circumferential seat disposed inside the gate valve housing or line stop fitting;
• the completion plug comprising a cylindrical body having a distal surface for engaging the insertion tool, a proximal surface that faces the pipe and a sidewall disposed between the distal and proximal surfaces, the sidewall comprising an outer circumferential slot for accommodating a circumferential seal, the completion plug also accommodating a normally-closed check valve, the check valve having an open distal end for receiving a check valve actuator and a proximal end in communication with the pipe;
• aligning the check valve actuator with the check valve and opening the check valve to provide communication between proximal and distal surfaces completion plug;
• and
• pressing the completion plug proximally until the proximal surface of the completion plug engages the circumferential seat of the gate valve housing or line stop fitting.