Abstract: A leak detection system for the detection and monitoring of pressurized refrigerant systems, primarily walk-in refrigeration units in stores or storage facilities, manages, monitors and controls the refrigeration system which store and preserve perishables. The system includes a gas refrigerant detector and a monitor and relay system to alert the store personnel and remote monitoring stations that a problem exists by detecting the presence of gas outside the system within the refrigeration units, assessing the magnitude of the problem, and providing an emergency shutoff means to close and contain the refrigeration system contents in the event a substantial refrigeration leak is detected, closing the system until system repairs are made and the system is reset.