Mueller Industries 521-398 Black Iron Reducing Coupling 2.5x2in Fip

Product Description

The MUELLER INDUSTRIES 521-398 is a black iron reducing coupling designed to connect two female-threaded pipes of differing diameters within gas, fuel, and industrial piping systems. Built from black iron, this fitting transitions from a 2.5-inch FIP inlet to a 2-inch FIP outlet and measures 3.6 inches in length. It is suited for use by licensed plumbers, pipefitters, and HVAC technicians working on systems that carry LP gas, natural gas, lubricants, oils, or greases. This fitting is not rated or approved for potable water service.

This reducing coupling sees common use in residential and light commercial gas distribution lines, oil transfer systems, and industrial lubrication piping. The FIP-to-FIP configuration allows it to thread directly onto male-ended pipe or nipples on both the inlet and outlet sides, making it a straightforward component in reducer installations where a pipe run steps down from 2.5 inches to 2 inches.

Key Features

• Reduces from 2.5-inch FIP inlet to 2-inch FIP outlet in a single fitting
• Black iron construction suitable for gas, oil, grease, and LP fuel service
• Female threaded on both ends for direct connection to male-threaded pipe or nipples
• Overall length of 3.6 inches keeps the fitting compact in tight runs
• Not approved for potable water applications

Compatibility

Designed as an OEM-style black iron fitting for use in gas, fuel, lubricant, and oil piping systems requiring a female-threaded reducer from 2.5 inches to 2 inches.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable local codes and IFGC requirements. Shut off gas or fluid supply and depressurize the line completely before removing or installing any fitting. Apply an approved thread sealant or PTFE tape rated for gas service to all male threads before assembly. Do not use this fitting in potable water lines.

Technical Specifications

• Inlet Diameter: 2.5 inches
• Inlet Connection: FIP (Female Iron Pipe)
• Outlet Diameter: 2 inches
• Outlet Connection: FIP (Female Iron Pipe)
• Product Length: 3.6 inches
• Material: Black Iron

Standard Information

• Brand: MUELLER INDUSTRIES
• Manufacturer Part Number: 521-398