HVAC Procedure and Performance Guide

TASK: Install manual balancing (volume) damper

Training for this procedure can be found in these courses:

                         103 – Basic Sheet Metal  and  205 – HVACR High Efficiency Ventilation


Manual balancing (volume) damper must be installed according to manufacturer’s specifications and job specifications.  Damper must not rattle with airflow and damper regulator must be accessible for adjustment. Applicable safety procedures must be followed.


  1. Review manufacturer’s specifications and job specifications.
  2. Collect tools, equipment and materials.
  3. Put on safety and protective equipment and apparel.
  4. Locate damper.
  5. Determine size and shape of damper required.
  6. Insert damper.
    • Sleeve-mounted in flexible duct:
      • Install damper blade in metal sleeve.
      • Install regulator on blade shaft on outside of sleeve.
      • Cut duct, insert sleeve and secure with clamps.
    • Single-blade type in metal duct:
      • Remove duct section.
      • Install damper blade in shaft inside duct.
      • Install regulator on shaft outside duct.
      • Replace duct section.
    • Factory-fabricated multi-blade damper in metal duct:
      • Determine mounting dimensions and mounting requirements for damper.
      • Remove duct section and prepare for damper installation according to specifications.
      • Install damper in duct and replace duct section.
      • Install damper linkage and manual regulator outside duct
  7. Check damper for free operation through full regulator travel; correct any interference with blade movement.
  8. Replace duct insulation when damper installation is completed.
  9. Remove safety and protective equipment and apparel.
  10. Gather tools, equipment and leftover materials and leave work site clean.