For a Messana system to automatically call for heating or cooling, the temperature would have to drop below or rise above the hysteresis band [set point – 0.4°F in heating and set point + 0.4°F in cooing] depending on the operative mode (heating or cooling). The hysteresis band is also known as the “comfort zone” which prevents the hydronic system from cycling on and off and wasting energy.
The default value for the temperature difference is 0.4°F. So, if you are in heating and your set point is set to 72°F, your system will not call for heating until the temperature drops below 71.6°F and will stop when the temperature returns to 72°F. Likewise, if you have a 65°F set point in cooling, the system will not call for cooling until the operative temperature rises above 65.4°F.