Compression coupler VIEGA 4715 Mufa 20 Pexfit — for 20 mm PEX pipes

VIEGA 4715 Mufa 20 Pexfit — for 20 mm PEX pipes is a compression coupler intended for joining 20 mm cross-linked polyethylene (PEX) pipes in potable water and heating systems. The fitting creates a mechanical sealed joint designed for straight connections, allowing installers to form a pressure-resistant link between two PEX pipe ends. It is suitable for use in residential and light commercial applications where PEX piping is specified.

Advantages

The compression design provides a secure mechanical connection without the need for soldering or adhesive, reducing on-site preparation and enabling faster assembly. Manufactured by VIEGA, the coupler is produced to industry tolerances that support consistent sealing and alignment of PEX pipes. Its compact form factor saves installation space in confined cavities and behind fixtures, while compatibility with 20 mm PEX minimizes the need for additional adaptors.

Suitable for

• Connecting two 20 mm PEX pipes in straight runs
• Potable water supply lines in residential buildings
• Domestic heating circuits and radiator connections
• Repair or replacement of existing 20 mm PEX segments

Key specifications

• Type: compression coupler for PEX piping
• Pipe diameter compatibility: 20 mm
• Connection style: mechanical compression joint for straight coupling
• Application: potable water and heating systems
• Material characteristics: corrosion-resistant materials suitable for PEX systems

How to use

Prepare both PEX pipe ends by cutting them squarely and removing any burrs or deformation. Slide the compression components onto the pipe as required by the coupler design, insert the pipe ends fully into the coupling body, and tighten the compression nut(s) or ring to the manufacturer-recommended torque using appropriate tools. Verify alignment and confirm the joint is fully seated. After assembly, perform a pressure test of the system according to local regulations and standards to ensure the connection is leak-free.

Usage recommendations

Use with 20 mm PEX pipes only and follow local plumbing codes. Select the correct installation tools and torque settings indicated by VIEGA. Avoid excessive bending at the joint and support piping runs to prevent mechanical stress. Inspect joints after pressure testing and before concealing them within walls or floors.