Io Hvac Controls SD-18 Round Auxiliary Zone Damper

Product Description

The IO HVAC CONTROLS SD-18 is an 18-inch round auxiliary zone damper designed to control airflow in ducted HVAC zoning systems. It installs inline within round ductwork and works in conjunction with a zone control board to open or close airflow to individual zones based on thermostat demand. The SD-18 is built for residential and light-commercial forced-air applications where precise zone control is required. Licensed HVAC technicians typically specify and install this damper as part of a multi-zone system retrofit or new construction zoning layout.

The SD-18 fits 18-inch round duct and is suited for trunk-and-branch and plenum-to-zone duct configurations. It functions as an auxiliary damper, meaning it operates alongside a primary zone damper or control panel to help balance airflow across multiple zones. This makes it a practical choice for larger residential systems or small commercial spaces where a single zone damper is insufficient to manage airflow distribution effectively.

Key Features

• 18-inch round duct size for high-volume airflow applications
• Auxiliary zone operation compatible with standard zone control boards
• Compact footprint at 20.5 x 13 x 20.5 inches (width x height x depth) for tight mechanical spaces
• Weighs 11.75 pounds for manageable single-technician handling during installation

Compatibility

Designed as an OEM-style auxiliary zone damper for use in residential and light-commercial ducted forced-air HVAC zoning systems utilizing 18-inch round ductwork.

Installation Notes

Installation should be performed by a licensed HVAC technician in accordance with local mechanical codes and SMACNA ductwork standards. Power down the air handler and de-energize the zone control panel before making any wiring connections to the damper actuator. Secure the damper inline with the round duct using sheet metal screws and foil tape or duct mastic to maintain an airtight seal. Verify actuator wiring against the zone control board documentation before restoring power.