Southwark Metal FB_17-1/2X28-1/2 Furnace Return Air Duct Box

Product Description

The SOUTHWARK METAL FB_17-1/2X28-1/2 is a sheet metal furnace return air duct box built for residential and light commercial forced-air heating and cooling systems. Fabricated from hot dip galvanized steel, this box forms the return air plenum connection at the furnace cabinet, channeling airflow from the return duct system back into the unit. At 17.5 inches by 28.5 inches, it accepts a standard 16 x 25 filter, allowing filter installation directly at the air handler. Licensed HVAC technicians and sheet metal contractors install this component during new construction or system replacement.

This return air duct box is designed for use with upflow and downflow gas or electric furnaces where a dedicated return air connection box is required at the base or side of the cabinet. It is suited for residential new construction and retrofit applications where field-fabricated or supplier-sourced sheet metal plenums are standard practice. The 17.5 x 28.5 inch face dimension accommodates common furnace cabinet widths and integrates with standard rectangular duct systems. Its filter slot sizing for a 16 x 25 filter makes it a practical choice for applications where filter access at the unit is preferred.

Key Features

• Hot dip galvanized steel construction for corrosion resistance in air-handling environments
• 17.5 x 28.5 inch face dimensions sized for common residential furnace cabinets
• Accepts a standard 16 x 25 filter for integrated filtration at the unit
• Meets ACCA and SMACNA applicable standards for sheet metal duct fabrication
• Return air configuration for forced-air furnace system installations

Compatibility

Designed as an OEM-style sheet metal return air duct box for residential and light commercial forced-air furnace systems requiring a 17.5 x 28.5 inch return air opening with a 16 x 25 filter slot.

Installation Notes

Installation should be performed by a licensed HVAC technician or sheet metal contractor in accordance with SMACNA duct construction standards and local mechanical codes. Shut down and de-energize the furnace and air handler before beginning duct work. Seal all seams with UL-listed mastic or metal foil tape to maintain system static pressure and prevent air bypass. Secure the box to the furnace cabinet and duct system using sheet metal screws at standard spacing per SMACNA guidelines.

Technical Specifications

• Material: Hot Dip Galvanized Steel
• Face Dimensions: 17.5 x 28.5 inches
• Filter Size: 16 x 25 inches
• Type: Return Air Duct Box
• Applicable Standards: ACCA, SMACNA

Standard Information

• Brand: SOUTHWARK METAL
• Manufacturer Part Number: FB_17-1/2X28-1/2