Air Flow Products RE054 Reducer Increaser 5 to 4 Inch

Product Description

The AIR FLOW PRODUCTS RE054 is a duct reducer-increaser fitting designed to transition between a 5-inch and 4-inch round duct diameter. This type of fitting is a standard component in forced-air HVAC systems, used to step down or step up airflow between duct sections of different sizes. It maintains a consistent airflow path while reducing turbulence at the transition point. HVAC technicians and sheet metal installers typically work with this fitting during duct fabrication, system balancing, or retrofit installations where trunk lines or branch runs require a size change.

This fitting is suited for residential and light commercial forced-air applications. It is commonly installed at branch takeoffs, air handler outlets, or inline duct runs where a 5-inch duct must connect to a 4-inch duct, or where an increase from 4 inches back to 5 inches is needed. The symmetrical reducer-increaser design allows it to serve both directions depending on installation orientation.

Key Features

• Transitions between 5-inch and 4-inch round duct diameters
• Bidirectional design functions as both reducer and increaser depending on orientation
• Standard round duct fitting suitable for forced-air HVAC duct systems
• Compact fitting profile minimizes disruption to duct layout

Compatibility

Designed as an OEM-style round duct transition fitting compatible with standard 5-inch and 4-inch round duct systems used in residential and light commercial forced-air HVAC installations.

Installation Notes

Installation is performed by licensed HVAC technicians or qualified sheet metal installers. Power down the air handling unit and close the system before cutting into or modifying duct runs. Secure the fitting to adjoining duct sections using sheet metal screws and seal all joints with UL 181-rated foil tape or mastic sealant in accordance with local mechanical codes. Verify airflow direction and system balance after installation.

Technical Specifications

• Large End Diameter: 5 inches
• Small End Diameter: 4 inches
• Fitting Type: Reducer-Increaser

Standard Information

• Brand: AIR FLOW PRODUCTS
• Manufacturer Part Number: RE054