An air handling unit (AHU) controller is ...

• A. A controller that coordinates network traffic.
• B. The controller that contains inputs and outputs required to operate large central-station air handling units.
• C. A device used to monitor outdoor air quality.
• D. A controller that powers air handlers.

Answer: (B)

The main idea here is that the AHU controller is the device that handles all the control signals for a large central air handling unit. It contains the inputs from sensors (like temperature, pressure, humidity, and sometimes CO2) and the outputs to actuators (such as dampers, fans, and valves), coordinating them through control logic to maintain desired conditions and sequence equipment properly. It may also communicate with the building automation system using standard protocols, enabling centralized management of the AHU. This isn’t primarily about managing network traffic, monitoring outdoor air quality as its sole function, or supplying power to the air handler—the controller simply provides the control signals and logic the AHU needs to operate.