Automated, variable volume unloaders provide the ability to smoothly load/unload reciprocating compressors to maintain ideal operations in ever-changing environments. Potential advantages provided by this load control system include: maximizing unit capacity, optimizing power economy, maintaining low exhaust emissions, and maintaining process suction and discharge pressures. Obstacles foreseen include: reliability, stability, serviceability and automation integration. Results desired include: increased productivity for the compressor and its operators, increased uptime, and more stable process control. This presentation covers: (1) system design features with descriptions of how different types of the devices were developed, initial test data, and how they can be effectively operated; (2) three actual-case studies detailing the reasons why automated, hydraulically controlled, variable volume, head-end unloaders were chosen over other types of unloading devices; (3) sophisticated software used in determining the device sizings and predicted performance; (4) mechanical and field considerations; (5) installation, serviceability and operating considerations; (6) device control issues, including PC and PLC considerations; (7) monitoring of actual performance and comparison of such with predicted performance; (8) analysis of mechanical reliability and stability; and (9) preliminary costs versus return on investment analysis.