TinnerFlow
Equipment, Flex & Terminal Connections ยท Equipment & Terminals

Short flex duct to diffuser

Terminal connection

ConnectionInner-core clamp + outer jacket seal
SupportWide straps/saddles

Before you start

  • Confirm the approved flex length, diffuser collar size, ceiling elevation, route, support, and allowed bend radius.
  • Inspect the inner core, insulation, outer jacket, and diffuser collar for tears, crushing, or sharp edges.
  • Keep the flex route short and direct.
  • Verify the diffuser boot is independently supported.

Tools and materials

Approved insulated flex duct, diffuser boot, approved draw bands or clamps, inner-core sealant or tape, jacket-seal materials, wide straps or saddles, cutter, snips, marker, and hand tools.

Lay it out

  1. Measure the shortest direct route from branch to diffuser.
  2. Allow enough length for full collar engagement without compression.
  3. Plan support points to prevent sag or a sharp bend at the boot.

Set and support it

  1. Support the diffuser boot independently.
  2. Install wide supports that do not crush the flex.
  3. Keep the flex fully extended during installation.

Make the connection

  1. 1

    Cut the flex square.

  2. 2

    Pull the jacket and insulation back from the inner core.

  3. 3

    Slide the inner core fully over the diffuser collar to the bead or required depth.

  4. 4

    Secure the inner core with the approved band or clamp.

  5. 5

    Seal the inner-core connection.

  6. 6

    Pull the insulation and jacket back over the collar.

  7. 7

    Seal the outer jacket continuously.

  8. 8

    Support the flex to remove sag and sharp bends.

Check the install

  • The inner core is fully extended.
  • No kink, compression, or sharp bend remains.
  • The inner-core connection is mechanically secured and sealed.
  • The vapor jacket is continuous.
  • The diffuser boot carries its own load.

Common mistakes

  • Using excess flex to cover a bad route.
  • Compressing the inner core.
  • Supporting flex with narrow wire or strap.
  • Connecting only the outer jacket.

Stop and ask

Stop if flex is being used to cover excessive offset or length, the core is torn, the insulation is crushed, or the diffuser lacks independent support.