3/4" FNPT x Copper ProPress Dielectric Union P-571NL Lead Free | Legend Valve

Legend Valve P-571NL – 3/4" FNPT x Copper Press Dielectric Union (Lead Free)

The Legend Valve P-571NL is a lead-free dielectric union designed to connect copper press fittings to iron or steel pipe using a 3/4" female NPT thread. It prevents galvanic corrosion at the joint between dissimilar metals — a critical requirement in residential and commercial plumbing systems.

Key Features

• Connection Type: 3/4" FNPT (Female National Pipe Thread) x Copper Press
• Lead Free: Compliant with NSF/ANSI 61 and Safe Drinking Water Act requirements
• Dielectric Isolation: Prevents galvanic corrosion between copper and ferrous pipe
• Part Number: P-571NL | LID: D5-1
• Material: Brass body with dielectric insulation
• Application: Potable water, hot and cold supply lines

Ideal For

Plumbers and contractors connecting copper press systems to threaded iron or steel pipe in residential, commercial, or light industrial applications. Compatible with standard press tools.

Available at AC Construction Depot – Charlotte, NC

In-store pickup available same day in Pineville, NC. Serving contractors across the greater Charlotte metro area. Call us at 704-835-1086 for stock confirmation.

Frequently Asked Questions — Press Fittings

1. What is a press fitting, and how does it work?

A press fitting is a no-solder, no-flame plumbing connection that uses a specially designed tool to mechanically compress a fitting onto a copper pipe. The fitting contains a pre-installed EPDM or HNBR O-ring that creates a watertight seal when the jaws of a press tool compress the fitting’s collar. The result is a permanent, leak-free connection in seconds — no torch, no flux, no open flame required.

2. What tools do I need to make a press connection?

You need a compatible press tool (such as a Viega, Milwaukee, Ridgid, or DEWALT press tool) with the correct jaw size for the fitting diameter. Most press fittings use standard M-profile jaws, but always verify compatibility with the fitting manufacturer’s spec sheet. You do not need any soldering equipment, flux, or heat source.

3. Are press fittings compatible with all copper pipe types?

Press fittings are compatible with Type K, Type L, and Type M copper tubing — the three most common types used in residential and commercial plumbing. They are not designed for use with CPVC, PEX, or other non-copper pipe without a specific adapter fitting rated for that material. Always confirm the fitting’s listed compatibility before installation.

4. Can press fittings be used on a live (wet) pipe?

Yes — one of the biggest advantages of press fittings is that they can be made on wet or damp pipe, unlike soldered joints which require a completely dry pipe. This makes press fittings especially valuable for repairs and retrofits where fully draining the system is impractical. However, the pipe must be free of debris and the O-ring seating area must be clean and undamaged.

5. How do I know if a press connection was made correctly?

Every press fitting has a visual indicator built into the O-ring or collar that confirms a proper press was made. After pressing, inspect the fitting — if the O-ring is visible and the collar is uniformly compressed with no gaps, the connection is good. An unpressed fitting will leak immediately when the system is pressurized, making it easy to identify during pressure testing. Always pressure-test the system before closing walls or concealing piping.

6. What pipe preparation is required before pressing?

Proper pipe prep is critical for a leak-free press connection:

• Cut the pipe square using a pipe cutter (not a hacksaw, which leaves burrs)
• Deburr and ream the pipe end inside and out
• Clean the pipe end with a clean cloth to remove debris, oil, or oxidation
• Mark the insertion depth on the pipe before inserting into the fitting
• Inspect the O-ring in the fitting — it must be seated properly and free of damage or debris before pressing

7. Are press fittings approved for use in walls, slabs, and concealed locations?

Yes — press fittings are approved for concealed and embedded installations in most jurisdictions when installed per the manufacturer’s instructions and applicable plumbing codes (IPC, UPC). They are listed to ASME B16.18 and ASME B16.22 standards and carry NSF/ANSI 61 certification for potable water. Always verify with your local Authority Having Jurisdiction (AHJ) and confirm the specific fitting’s listings before rough-in inspection.

8. What is the pressure and temperature rating for press fittings?

Most copper press fittings are rated for:

• Up to 200 PSI working pressure for water service
• Up to 200°F (93°C) for hot water systems
• Ratings vary by O-ring material — EPDM O-rings are standard for water; HNBR O-rings are used for oil, gas, and higher-temperature applications

Always check the specific fitting’s data sheet for the exact pressure/temperature rating for your application.

9. Can press fittings be used for gas lines?

Standard press fittings with EPDM O-rings are NOT rated for gas service. For gas applications, you need press fittings specifically rated and listed for gas, which use HNBR (yellow) O-rings and carry the appropriate gas listing. Using a water-rated press fitting on a gas line is a serious safety hazard. Always confirm the fitting’s gas listing before any gas installation.

10. Are these fittings available for same-day pickup, and do you carry a full range of sizes?

Yes — we stock a range of press fittings at AC Construction Depot in Pineville, NC (serving the greater Charlotte area), available for same-day pickup. Our inventory includes tees, reducers, couplings, elbows, and dielectric unions in common sizes. Stock levels vary by SKU, so call us at 704-835-1086 to confirm availability on the size and configuration you need before making the trip.