Several different balancing valve technologies exist in today’s market; some are new and some have been around for decades. A working knowledge of the entire range of options will serve you well when selecting the correct approach for your specific hydronic or plumbing system project.
Manual (also known as pressure-dependent or static) balancing valves have been the industry workhorses for decades. They are called “static” balancing valves because once they are adjusted, there is no movement of the internal components. Most have two pressure-test ports (PT) for measuring differential pressure across the internal flow restriction, which is then correlated to a flow rate using a graph or chart of some type.