How to Adjust Air Flow for an HVAC Flex Duct

Heating, ventilation and air conditioning systems operate with ducts routed throughout a building to deliver heated or cooled air. Flex ducts, as the name implies, bend around obstacles and corners without losing structural integrity so air continues to flow through them. An adjustable damper is mounted inside the flex duct at the point where it attaches to the main duct before branching off. The damper control consists of a metal rod extending from the side. Adjusting airflow with the damper takes less than a minute.

Things You'll Need

• Folding ladder
• Flat-blade screwdriver

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Instructions

1. • 1

     Set up the ladder below the flex duct at the joint with the main ductwork. A ladder is not necessary if you can reach the flex duct, but if you use a ladder, recruit a helper to hold the ladder steady.

   • 2

     Insert the screwdriver into the notch on the end of the adjustment rod on the side of the flex duct.

   • 3

     Turn the slot in the rod perpendicular to the duct to close the damper inside. This shuts off airflow.

   • 4

     Turn the slot in the rod so it is in line with the flex duct to open it fully for maximum airflow.