Energy conservation dictates a redirection of manual adjustment to automatic controls. Consequently, designed parameters are more apt to remain as prescribed. System operation knowledge "up front" allows for better understanding of the system's operation during commissioning. Recent improvements in local loop control have enabled control systems to be designed and manu­factured with actual set points or parameters factory-calibrated, or "built in", to the system prior to installation.

This paper covers the enhancements incorporated in local loop control systems over the last ten years. It will show that pneumatic control, although in existence for a long time and considered outdated, has not died or, for that matter, stepped to the wayside. Rather, pneumatic control has joined with state-of-the-art computerized control systems, remaining a desirable control arrangement choice for HVAC systems.