How the 12 Inch Back Draught Damper Seals an Idle Duct
At 12 in the reverse draught through a stopped fan is substantial, and in winter it is expensive. The damper blocks it with spring-loaded aluminium flaps seating on a rubber seal, inside a galvanized sheet steel housing. Nothing about it is powered: airflow alone opens it and spring pressure alone closes it.
Mounting a Backdraft Shutter in the Right Place
Horizontal or vertical mounting both work, thanks to the spring rather than gravity holding the flaps shut. Install it after the fan, flaps opening downstream. There is a small pressure penalty to accept, and at this size it is a fair trade against the heat a stopped fan otherwise loses. Dust on the rubber seat is the usual failure mode, so wipe it when you service the run. A flap that rattles at low output means the fan is not making enough pressure to hold it open cleanly.
Key Features
- Spring-Loaded Aluminium Flaps: Open on airflow and close under spring pressure, with nothing to power.
- Rubber Seal: Closes the gap at the seat so a stopped duct actually stays shut.
- Galvanized Steel Housing: Corrosion-resistant in the damp air an exhaust run carries.
- Horizontal or Vertical Mounting: Spring loading means it does not depend on gravity to close.
- 12 in Duct Fit: Matches Ruck 12 in components and standard 12 in ducting.
- Fully Mechanical: No wiring, no actuator and no control signal to lose.
Technical Specifications
| Specification | Value |
|---|---|
| Duct Size | 12 in |
| Housing | Galvanized sheet steel |
| Flaps | Spring-loaded aluminium |
| Seal | Rubber |
| Mounting | Horizontal or vertical |
| Operation | Airflow-opened, spring-closed |