Parker 66VL-5-4 Compression Tube Connector 1/4-18

Product Description

The PARKER 66VL-5-4 is a brass compression tube connector designed to join tubing to female NPT threaded ports in fluid and pneumatic systems. It features a compression end for 5/16-inch outside diameter tubing and a 1/4-18 FNPT threaded end, allowing a secure, leak-resistant connection without welding or brazing. Rated to 500 psi maximum working pressure, this fitting handles a temperature range from -30 degrees F to 275 degrees F. It meets ISO 6149 and SAE J1926 standards and is suited for installation by licensed plumbers, HVAC technicians, and hydraulic system mechanics working on instrumentation, refrigeration, or fluid transfer lines.

This connector is used in residential and light commercial applications where tubing must transition to an FNPT-threaded port on valves, manifolds, gauges, or equipment housings. The brass construction makes it appropriate for use with water, air, oil, and many compatible refrigerants or hydraulic fluids. Its compact single-piece body fits in tight spaces and requires only standard compression fitting tools for installation.

Key Features

• Brass body construction for corrosion resistance and durability in fluid systems
• Compression x FNPT end connections for tool-accessible, no-weld installation
• Fits 5/16-inch outside diameter tubing with a 1/4-18 female NPT thread
• Rated to 500 psi maximum working pressure
• Meets ISO 6149 and SAE J1926 standards
• Operating temperature range from -30 degrees F to 275 degrees F

Compatibility

Designed as an OEM-style compression-to-FNPT fitting for fluid and pneumatic systems requiring a 5/16-inch OD tube connection to a 1/4-18 female NPT port.

Installation Notes

Installation is typically performed by licensed plumbers, HVAC technicians, or hydraulic mechanics. Depressurize and drain the system fully before removing or installing any compression fittings. Hand-tighten the compression nut onto the fitting body, then advance with a wrench per standard compression fitting practice — do not overtighten, as brass fittings can deform the ferrule. Verify the system is leak-free under pressure before returning it to service.