When HVAC airflow is unbalanced, don't just focus on the diffuser damper settings.

During HVAC commissioning, I once encountered a VAV system where the airflow just wouldn't balance. At the start, the team kept adjusting the diffuser dampers, but as soon as one room improved, the adjacent one went off. Later, I checked it with the TAB technician and found that the upstream static pressure setpoint was too low, and a branch flexible duct was crushed, making the terminal units…