NATE HVAC Support Technician Practice Test 2026 - Complete Exam Prep

Airflow noise is often caused by turbulence created when a damper isn’t fully closed. If the damper blade is left open or only partially closed, air rushes through the opening and can produce whistling, rushing, or fluttering sounds in the ducts. The remedy is to verify the damper position for the affected zone and ensure the damper blade can move freely and fully to the closed position when that zone isn’t calling for air. Also check for any binding of the actuator, bent blades, or gaps between the blade and frame that let air escape.

Duct insulation won’t typically generate or eliminate the noise coming from the airflow itself, though it can affect sound transmission. Tightening blower screws may reduce vibration noise, but it doesn’t address the common cause of airflow noise tied to damper positioning. Checking refrigerant charge relates to cooling performance, not the path of airflow.