This document details the flow verification and commissioning procedures in HVAC plants, water distribution can be accomplished at constant or variable flow. Each type of distribution system has advantages and disadvantages. Today variable flow systems using electronic 2-way control valves became generally accepted as the industry standard due to their benefits. The main reason for becoming the industry standard is reduced pumping cost, which is a result of pump head and flow. Meaning, the more control valves are closing, the lower the total flow. Another reason is that the plant can be designed with a diversity factor because flow is only needed where energy is demanded. Besides these advantages, there are disadvantages in today’s variable flow systems.
