What is a key statement regarding the use of automatic air vents on a circulator?

The statement that automatic air vents should never be used on the suction side of a circulator is based on the principles of fluid mechanics and the operational requirements of heating and cooling systems. When air vents are placed on the suction side, there is a risk of drawing air into the pump, which can lead to cavitation. Cavitation occurs when vapor bubbles form in the liquid due to low pressure, and when these bubbles collapse, it can damage the pump and reduce efficiency.

By positioning automatic air vents correctly, typically on the discharge side, air can be removed from the system without compromising the circulator's operation. This helps maintain the pump's efficiency, as well as ensuring that proper water flow and pressure are maintained throughout the system. Therefore, utilizing air vents in the correct location is crucial for optimal system performance and longevity of equipment.