Which statement about automatic air vents is accurate?

The statement that automatic air vents should not be used on the suction side of a circulator is accurate because air traps can cause significant operational issues when present in this area. When an automatic air vent is installed on the suction side, it can allow air to enter the system, leading to reduced system efficiency and potential cavitation of the circulator pump. This cavitation occurs when there is an area of low pressure that allows vapor bubbles to form, which could lead to noise, decreased pump performance, and eventual damage to the pump itself.

In contrast, when installed on the discharge side, automatic air vents effectively remove trapped air, allowing for a more efficient flow of fluid throughout the system without risk of air entering where it could lead to these complications. This highlights the importance of proper placement in ensuring the smooth operation of the heating or cooling system and maintaining its efficiency.