Seal-tite 96-212818 Return Air Support Box Top

Product Description

The SEAL-TITE 96-212818 is a return air support box top designed for residential and light commercial HVAC return air plenum assemblies. Fabricated from galvanized steel, it measures 21.25 inches by 28.75 inches by 18 inches and features 3.5-inch vertical hemmed edges along the perimeter. Those hemmed edges stiffen the panel, eliminate exposed raw-steel cuts, and reduce the risk of installer lacerations during handling. The galvanized finish resists corrosion in attic, crawlspace, and mechanical-room environments where condensation and humidity are common concerns for HVAC technicians.

This support box top is suited for return air configurations requiring a 21.25 x 28.75 x 18-inch opening, typically found in residential forced-air systems and small commercial applications. It is intended for use during new construction plenum builds or retrofit return air duct modifications. HVAC sheet metal installers and service technicians will find it compatible with standard return air framing setups where a rigid, dimensionally accurate top panel is required to complete the plenum enclosure.

Key Features

• Galvanized steel construction provides corrosion resistance in high-humidity HVAC environments
• Dimensions of 21.25 x 28.75 x 18 inches match standard return air plenum openings
• 3.5-inch vertical hemmed edges add structural rigidity and eliminate exposed sharp edges
• Precision-formed profile supports consistent fitment and smooth airflow transition at the return air plenum
• Compatible with typical residential and light commercial forced-air return air duct assemblies

Compatibility

Designed as an OEM-style replacement and new-installation component for return air plenum support box assemblies requiring a 21.25 x 28.75 x 18-inch top panel with 3.5-inch hemmed vertical edges.

Installation Notes

Installation of this component is performed by licensed HVAC technicians or qualified sheet metal installers. Power down the air handling unit and confirm the system is de-energized before beginning any plenum modification or duct work. Wear appropriate cut-resistant gloves when handling sheet metal components, even those with hemmed edges. Local mechanical codes, including applicable sections of the IMC, should be consulted to confirm plenum construction requirements for the jurisdiction.

Technical Specifications

• Length: 28.75 inches
• Width: 21.25 inches
• Height: 18 inches
• Hemmed Edge Height: 3.5 inches
• Material: Galvanized Steel

Standard Information

• Brand: SEAL-TITE
• Manufacturer Part Number: 96-212818