VIEGA reducing tee 18x18x15 mm N26, copper plumbing fitting

The VIEGA reducing tee 18x18x15 mm N26 is a copper plumbing fitting designed to join three copper pipes while creating a reduced-diameter branch. Manufactured for use in potable water and heating systems, this tee provides a compact solution for changing pipe size from 18 mm to 15 mm within a single fitting. The product is intended for installations in domestic and light commercial environments where a stable, leak-resistant branch connection is required and compatible with standard copper tubing.

Advantages

This VIEGA reducing tee is made of copper, offering corrosion resistance and long service life in common plumbing environments. Its N26 design ensures precise dimensional compatibility with 18 mm and 15 mm copper pipes, simplifying transitions between pipe sizes without additional adapters. The single-piece construction reduces the number of joints and potential leak points, supporting reliable performance in potable water and heating applications.

Suitable for

• Domestic cold and hot water distribution systems
• Residential and small commercial heating circuits
• Piping runs where a branch reduction from 18 mm to 15 mm is required
• Repairs and modifications of existing copper pipe networks

Key specifications

• Material: copper
• Configuration: reducing tee (two inlets/outlets of equal diameter, one reduced branch)
• Connection sizes: main run 18 mm × 18 mm; branch 15 mm
• Intended fluids: potable water and heating fluids compatible with copper
• Typical installation environment: indoor domestic and light commercial plumbing

How to use

Prepare the copper pipes by cutting squarely and deburring the ends to ensure full insertion. Clean the pipe surfaces and the inside of the fitting to remove oxides and contaminants. Install the tee by joining the 18 mm pipes to the main run ends and inserting the 15 mm pipe into the reduced branch. Secure the joints according to the chosen joining method suitable for copper fittings—commonly soldering (capillary brazing) or approved mechanical joining techniques—following local plumbing codes and manufacturer recommendations for heating and potable water systems.

Usage recommendations

Confirm compatibility of the VIEGA reducing tee with the specific copper tube standard used in your installation and follow local regulations for potable water and heating systems. When soldering, use appropriate flux and heating methods to avoid overheating nearby components; when using mechanical connectors, ensure proper torque and sealing. Pressure-test the system after installation to verify leak-free operation before commissioning.