An installer is asked to design a two zone radiant panel heating system. Due to panel construction, two independently controlled water temperatures are necessary. These will be achieved with two independently operating motorized 3-way mixing valves and their associated electronic controllers. A thermostatic mixing valve with a Cv of 3.0 will be used to boost the inlet water temperature to the cast-iron gas-fired boiler to 130 ºF to avoid sustained flue gas condensation. A schematic for the as-installed system is shown below. Can you spot several details that will lead to problems? How would you design the system differently?