The REGAL Series A-550 switchover modules are designed to automatically change the gas supply from one vacuum regulated source (cylinder or ton container) to a second, standby source. Once the initial source is incapable of supplying the necessary demand for the system, an increase in vacuum activates the module to close that source while simultaneously opening the standby. This allows for continuous feeding of gas for the system. The depleted source of gas can then be safely and easily replaced using the normal procedure.