The 571-2 is a two-way heat motor zone valve. Taco's heat motor zone valves combine with a single circulator to provide efficient, reliable zoning. Adding heat motor zone valves to your hydronic system will provide you with complete control over your system's distribution of heat—and complete comfort in any room. A zoned system has greater comfort and lower energy costs then a non-zoned system. With Taco's heat motor zone valves, it is easier than ever to incorporate zones in your building. A removable head protects the 571-2's components and makes it easy to service the valve without disrupting any connections. All Taco heat motor zone valves include a manual bypass lever. Temporary temperature adjustments and circulation in a power outage are no issue for these valves. An inverted globe valve design is coupled with a bellows seal to guarantee accurate shut-offs and leak-free operation.