An economical way to provide a safe, balanced system for stand-alone master tempering valves. The system monitors return line temperature, and automatically directs water to the cold side of the valve (if within set point) or to the hot water source (if too cool). This is accomplished with Powers exclusive automatic balancing valve (ABV), featuring parafin-based, advanced actuation technology. Each HydroGuard system is mounted on heavy-duty welded struts, comes fully assembled and factory tested, includes temperature/pressure gauges for system diagnostics and a return-line flow meter to insure minimum flow requirements are met. ABV Loop assemblies can also be purchased without the master tempering valve for existing installations where consistent water temperature is a problem.