Introducing the NIBCO 3/8 in. Sweat x 1/4 in. Sweat Copper Reducing Coupling—a lead-free copper fitting engineered for reliable, soldered connections between a 3/8 in line and a 1/4 in line. This two-end reducer is built for durability in residential and light commercial plumbing, delivering a clean, compact transition in cramped spaces.
Key specifications
- End 1 diameter: 3/8 in; End 1 type: Sweat
- End 2 diameter: 1/4 in; End 2 type: Sweat
- Material: Lead-free copper
- Maximum Working Pressure: 912 psi
- Maximum Working Temperature: 400°F
- NSF Listing: Yes
- Compatible Pipe Material: Copper
- Package Type: Bagged; Quantity: 1 piece
- Brand: NIBCO; Product Type: Reducing Coupling
Why this reducing coupling matters
- Lead-free copper ensures safer drinking water and long-term reliability in both hot and cold lines.
- Sweat (solder) ends on both sides provide a robust, watertight joint when installed with standard flux and soldering techniques.
- The 3/8 in to 1/4 in reduction is ideal for compact transitions in tight spaces where traditional fittings won’t fit.
- High pressure rating (912 psi) makes it suitable for common domestic water systems and many radiant or distribution layouts.
- NSF-listed, so you have an extra level of confidence in compliance and safety for potable-water applications.
Ideal use cases
Use this NIBCO copper reducing coupling to connect a 3/8 in copper supply line to a 1/4 in branch line in under-sink plumbing, appliance connections, or compact distribution runs. It’s particularly valuable when space is limited and a reliable, soldered joint is preferred over crimp or push-to-connect styles. Perfect for new installations and reliable repairs where copper piping is the material of choice.
Installation tips
- Cut the copper pipe ends cleanly and squarely; deburr the inner edge for a smooth fit.
- Clean the pipe ends and inside of the fitting to remove oxidation and ensure a strong solder joint.
- Apply an even layer of flux to the outside of the pipe and the inside of the fitting.
- Assemble the reducing coupling, and heat evenly with a compatible flame until the solder flows and seals the joint.
- Wipe away excess flux, allow the joint to cool, and test for leaks with a soap-and-water solution or pressure test.
With its lead-free copper construction, reliable sweat joints, and a compact 3/8 in to 1/4 in reduction, this NIBCO fitting is a practical, long-lasting choice for anyone working with copper piping. It’s designed to perform consistently under typical household water pressures and temperatures, helping you complete plumbing projects smoothly and with confidence.
