What is the definition of a vav valve? VAV stands for Variable Air Volume, and is a type of HVAC system control valve. It is designed to regulate the amount of air that is circulated through a system, usually in response to changes in temperature or pressure. The main purpose of a VAV valve is to ensure that a building’s interior is kept comfortable and energy efficient. A VAV valve typically consists of a control valve, an actuator, a controller, and a damper. The control valve is responsible for regulating the flow of air, while the actuator is responsible for controlling the opening and closing of the damper. The controller is responsible for monitoring the system and sending signals to the actuator to open and close the damper. When the temperature in the room rises, the controller will signal the actuator to open the damper, allowing more air to enter the room and cool it down. Conversely, when the temperature in the room falls