TinnerFlow
Elbows & Offsets ยท Elbows & Offsets

Rectangular square-throat elbow with vanes

Abrupt 90-degree turn

ConnectionFlanged or S-drive
SupportSupport at fitting

Before you start

  • Confirm the square-throat elbow is approved for the system and that turning vanes are required.
  • Inspect every vane, vane rail, fastener, rail penetration, seam, and flange before lifting.
  • Check for loose, reversed, bent, missing, or poorly seated vanes.
  • Verify there is enough access to inspect the vane assembly before the fitting is concealed.

Tools and materials

Square-throat elbow with complete vane assembly, approved flanged or S-and-drive joint components, gasket, corners, cleats, fasteners, sealant, clamps, level, inspection light, and fitting support.

Lay it out

  1. Mark inlet, outlet, airflow direction, and the elbow plane.
  2. Confirm the vane curve follows the intended airflow path.
  3. Locate the support under the fitting body and keep access to the vane side.

Set and support it

  1. Set the elbow on its dedicated support before closing both joints.
  2. Keep the fitting square and prevent rotation.
  3. Support both straight runs independently.

Make the connection

  1. 1

    Inspect and count the vanes before installation.

  2. 2

    Verify the vane rails are tight and all penetrations are sealed as required.

  3. 3

    Align and connect the inlet without racking the elbow.

  4. 4

    Recheck fitting square and outlet centerline.

  5. 5

    Connect the outlet.

  6. 6

    Seal the joint corners and any required rail penetrations.

  7. 7

    Inspect the vane assembly again before concealment.

Check the install

  • All vanes are present, aligned, and secure.
  • No vane is reversed or loose.
  • The elbow remains square and the joints are fully seated.
  • Rail penetrations are sealed where required.
  • No loose metal remains inside the fitting.

Common mistakes

  • Assuming the shop-installed vane assembly is complete without checking.
  • Installing a vane backward.
  • Racking the elbow to reach the second run.
  • Concealing the fitting before the vane assembly is inspected.

Stop and ask

Stop if the vane assembly is missing, loose, reversed, damaged, incomplete, or different from the approved fitting.