The ECM, wet rotor 00e VR1816 circulator from Taco has up to 18-foot shut-off heads and 16 gpm flow. With the turn of a dial, it provides self-sensing variable-speed operation in three different modes, including infinitely variable fixed speed for zoning with circulators, and constant pressure, self-adjusting, variable speed for zone valve applications. The circulator maintains a constant pressure differential in the system as heating load increases or decreases, and proportional pressure, self-adjusting, variable speed for panel radiators with thermostatic valves. Its LED displays operating mode and error code diagnostics. Other features include an easy-to-use dial to set operating speed or pressure control, an integral flow check (IFC) and dual electrical knockouts. 401/942-8000; www.taco-hvac.com.