There is low airflow or no air at a diffuser after startup. What do I check first?
Check install basics before blaming the unit: diffuser/grille installed, damper open/accessible, flex connected and not kinked, branch connected, fire/smoke damper open/reset as directed, and no blocked duct path.
Check device, damper, flex/branch, access, and VAV/fire-smoke involvement before blaming equipment.
Do not randomly move dampers, change controls, or tell the owner “the unit is bad” before install conditions are checked.
Check
Device/room/tag
Damper/access condition
Flex/branch connection
Fire/smoke/VAV involvement
Recent ceiling/finish work nearby
Steps
Confirm which room/device has low or no airflow.
Check visible diffuser/register/grille and damper handle position if accessible.
Inspect flex/branch connection for kinks, crushed liner, disconnection, or blocked path.
Check if a fire/smoke damper, VAV box, or balancing damper is involved.
Document and ask before changing control settings or damper positions outside direction.
Say this to your foreman
This diffuser/register at [room/tag] has low/no airflow. I checked visible connection, damper access, and flex/branch condition. Do you want me to inspect upstream, hold for TAB, or check a specific damper/VAV?