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Small brass union coupling with sweat and threaded ends

Nibco, Inc.

Nibco, Inc. 7334-LF 3/8 in Copper Union Cup MNPT coupling

SKU CH-G51M-58WV6

Connects 3/8 in copper tubing to 3/8 in male pipe threads with a sweat union rated to 623 psi and 200 Degrees F, meeting ASME B 16.18, NSF/ANSI 61 and NSF/ANSI 372

  • Lead-free copper meets NSF/ANSI 372 for safe potable water
  • 623 psi rating handles high-pressure plumbing systems reliably
  • 200 °F maximum temperature suits hot-water supply lines
  • Sweat cup to MNPT union joins copper tube to threaded pipe
  • Certified to ASME B16.18 and NSF/ANSI 61 standards

Potable-water copper union

This NIBCO 7334-LF union joins a 3/8-inch copper tube to a 3/8-inch male pipe thread in straight runs. It is rated for potable water service and meets ASME B 16.18, NSF/ANSI 61 and NSF/ANSI 372 standards. Installers use it where a removable joint is required on hot or cold supply lines.

623 psi pressure headroom

The fitting withstands up to 623 psi at 200 degrees F, giving ample margin for typical residential and light-commercial pressures. Systems that exceed either limit will need a higher-rated union. The cast copper body handles thermal cycling without deformation.

Cast copper body with sweat and threaded ends

One end is a cup sweat connection for 3/8-inch copper tube, the other a 3/8-inch MNPT thread for pipe or adapter. The straight union shape allows easy disassembly for maintenance or fixture replacement. No flare, compression or push-fit ends are provided.

Highlights

  • Lead-free copper meets NSF/ANSI 372 for safe potable water
  • 623 psi rating handles high-pressure plumbing systems reliably
  • 200 °F maximum temperature suits hot-water supply lines
  • Sweat cup to MNPT union joins copper tube to threaded pipe
  • Certified to ASME B16.18 and NSF/ANSI 61 standards

Specifications

BrandNIBCO

Questions about this item

Will the 3/8 in MNPT thread on this Nibco 7334-LF union mate with my existing 3/8 in copper pipe and fittings?

Yes — Side B is a 3/8 in MNPT connection and Side A is a 3/8 in copper cup (1/2 in OD), so it joins directly to standard 3/8 in copper tube and matching threaded components.

How can I verify the joint is sound after sweating the cup end and threading the MNPT end?

Pressurise the line up to the 623 psi rating and inspect for leaks; the union meets ASME B16.18 and NSF/ANSI 61/372, so a leak-free test confirms correct installation.

Does the box contain only the cast-copper union body, or are sealing washers and thread sealant included?

The package contains the straight union fitting only; PTFE tape or pipe dope for the MNPT threads and solder/flux for the sweat cup must be purchased separately.

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