{"product_id":"io-hvac-controls-sd-18-round-auxiliary-zone-damper","title":"Io Hvac Controls SD-18 Round Auxiliary Zone Damper","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe 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.\u003c\/p\u003e\u003cp\u003eThe 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.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e18-inch round duct size for high-volume airflow applications\u003c\/li\u003e\n\u003cli\u003eAuxiliary zone operation compatible with standard zone control boards\u003c\/li\u003e\n\u003cli\u003eCompact footprint at 20.5 x 13 x 20.5 inches (width x height x depth) for tight mechanical spaces\u003c\/li\u003e\n\u003cli\u003eWeighs 11.75 pounds for manageable single-technician handling during installation\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eDesigned 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.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eInstallation 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.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDuct Size\u003c\/strong\u003e: 18 inches round\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWidth\u003c\/strong\u003e: 20.5 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeight\u003c\/strong\u003e: 13 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDepth\u003c\/strong\u003e: 20.5 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 11.75 pounds\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: IO HVAC CONTROLS\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: SD-18\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"IO HVAC CONTROLS","offers":[{"title":"Default Title","offer_id":67952872161586,"sku":"SD-18","price":415.98,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/68323c27c54e9f0dc3067f687c08fcda_cb942622-6327-4e2a-9a78-e999039dc861.png?v=1791753545","url":"https:\/\/voomisupply.com\/products\/io-hvac-controls-sd-18-round-auxiliary-zone-damper","provider":"Voomi Supply","version":"1.0","type":"link"}