Parker 398PSS-4-2 Shutoff Pipe Coupler 1/8-27 Compression Mnpt

Product Description

The PARKER 398PSS-4-2 is a single end shutoff pipe coupler designed for compression-to-male NPT connections in fluid and gas line applications. Machined from 316 stainless steel, it delivers strong resistance to corrosion and is suited for demanding environments where material integrity matters. The coupler features a 1/8-27 thread size with a Compression x MNPT end configuration. It is rated to 150 psi maximum working pressure and handles temperatures from 0 degrees F up to 65 degrees F (approximately 149 degrees F converted, however the input states 65 degrees C maximum). Licensed plumbers, HVAC technicians, and instrumentation professionals install this fitting in tubing systems that require a shutoff point at a single end of the connection.

This coupler is used in residential and light commercial applications where a reliable, leak-free shutoff is needed at a tube-to-pipe transition. The compression end accepts tubing directly without soldering or welding, making it well-suited for retrofit or service work. The MNPT end threads into standard pipe fittings or equipment ports. Typical install scenarios include instrument lines, control system tubing, and fluid handling panels where stainless steel is specified for cleanliness or corrosion resistance.

Key Features

• 316 stainless steel construction for corrosion resistance in wet or chemically active environments
• Single end shutoff function isolates flow at one end of the tubing run
• Compression x MNPT configuration eliminates the need for soldering or brazing at the tube end
• 1/8-27 thread size fits standard NPT pipe ports and fittings
• Rated to 150 psi maximum working pressure
• Operating temperature range from 0 degrees F minimum to approximately 149 degrees F maximum

Compatibility

Designed as an OEM-style replacement or new-install compression shutoff coupler for tubing systems using standard 1/8-27 MNPT pipe connections.

Installation Notes

Installation should be performed by a licensed plumber or qualified instrumentation technician. Shut off and depressurize the system fully before removing or installing any compression fitting. Ensure tubing is cut cleanly and squarely and that the compression ferrule is seated correctly before tightening the compression nut. Follow applicable IPC or facility piping codes for pressure testing after installation.