Air Flow Products 850-1-000000-002018 Reducer Increaser 20x18

Product Description

The AIR FLOW PRODUCTS 850-1-000000-002018 is a duct reducer/increaser fitting designed to transition between two different duct sizes within a forced-air HVAC system. Reducer/increaser fittings are used to step airflow down or up between duct sections of differing cross-section, maintaining system balance and minimizing turbulence at the transition point. This unit carries a 20 x 18 size designation, meaning it connects a 20-inch duct opening to an 18-inch duct opening or vice versa. HVAC installers and sheet metal contractors are the primary trades that work with this type of fitting during new construction and retrofit duct work.

This fitting is suited for residential and light commercial forced-air duct systems where a change in duct dimension is required between the air handler, plenum, or trunk line and a smaller branch or downstream duct run. Typical install scenarios include transitioning from a main trunk line to a branch run, or adapting an existing duct opening to new equipment with a different collar size. Verify the size designation against your duct layout before installation.

Key Features

• Reducer/increaser configuration allows transition between two different duct sizes in a single fitting
• 20 x 18 size designation connects a 20-inch duct to an 18-inch duct opening
• Single-unit selling format - one fitting per order
• Compatible with standard forced-air duct installation practices

Compatibility

Designed as an OEM-style duct transition fitting for forced-air HVAC systems requiring a step-down or step-up between 20-inch and 18-inch duct sections. Verify duct dimensions and connection type against your specific system layout before ordering.

Installation Notes

Installation is typically performed by a licensed HVAC technician or sheet metal contractor. Shut down and lock out the air handling unit before cutting into or modifying any duct section. Secure the fitting with sheet metal screws and seal all joints with UL 181-listed mastic or foil tape per local mechanical code requirements. Do not force the fitting onto mismatched duct profiles - confirm opening dimensions before fastening.