Parker 391P-4-2 Compression Pipe Coupler 1/8-27 Nptf Brass

Product Description

The PARKER 391P-4-2 is a compression tube pipe coupler body designed to connect a plug-in stem fitting to a pipe thread port. Machined from brass, it accepts a 1/8-27 NPTF thread and is rated for a maximum working pressure of 150 psi and a temperature range of 0 to 150 degrees F. This fitting is used in compressed air, pneumatic control, and fluid handling lines where a secure, leak-resistant compression-to-pipe transition is required. Licensed plumbers, HVAC technicians, and industrial pipe fitters are the typical installers.

This coupler body suits light-duty pneumatic and fluid distribution systems in both residential and commercial settings. It is commonly installed at panel connections, instrument ports, or branch line takeoffs where a plug-in compression stem must transition to a threaded pipe port. The compact brass body fits into tight spaces and is well suited for control tubing runs in HVAC equipment, refrigeration panels, and pneumatic instrumentation circuits.

Key Features

• Brass construction for corrosion resistance in air and fluid service
• 1/8-27 NPTF thread provides a dry-seal mechanical connection at the pipe end
• Plug-in stem end accepts standard compression tube inserts for quick assembly
• 150 psi maximum working pressure suitable for light pneumatic and fluid lines
• Operating temperature range of 0 to 150 degrees F covers typical HVAC and industrial control applications

Compatibility

Designed as an OEM-style replacement or direct-use fitting for compression tube systems requiring a plug-in stem to pipe coupler body with a 1/8-27 NPTF thread connection.

Installation Notes

Installation should be performed by a qualified plumber, pipefitter, or HVAC technician. Depressurize and isolate the line completely before removing or installing any compression fitting. NPTF threads are designed for dry-seal assembly; apply thread sealant only if required by the system specification and local code. Inspect the compression stem seat and tube end for burrs or damage before making up the joint.