The Taco Priority Zoning Circulator combines the reliability of the 00 circulator with the convenience and efficiency of a PC board mounted switching relay package. Each zoning circulator has low and high voltage terminal strips for ease of electrical hookup, as well as a built-in priority switch. The priority switch allows the installer to choose the zone that requires the most attention and, when activated, run only that circulator. The priority zoning circulator can be used in conjunction with other circulators or zone valves. It is ideal for adding another zone, zoning with circulators, and for prioritizing under-sized zones.