Concentric Duct Kits are used with Roof Top Mounted HVAC equipment allowing the supply air to travel down into the building through an external duct that surrounds the central return air duct where the building air is allowed to return up to the unit. These kits are specific to a particular HVAC Unit so they must be selected for that unit. The options for air distribution at the end of the concentric duct kit include ceiling flush mount diffusers, drop box diffusers with grilles or drum louvers. Other options include an additional return air filter for supplemental air filtration and manually adjustable dampers on each grille or drum louver to control supply air flow in the different directions.
For concentric diffuser options without the duct kits, see Plenums Concentric Diffusers. For drop box diffuser options without duct kits and for supply only, see Plenums Drop Box Diffusers.
