A.y. Mcdonald 5421-325 Pressure Relief Valve 0.5 in Mpt

Product Description

The A.Y. MCDONALD 5421-325 is a lead-free pressure relief valve designed for residential and light commercial plumbing systems. Threaded with a 0.5-inch male pipe thread (MPT) connection, it provides automatic pressure relief at a 75 psi set point, protecting water lines, water heaters, and closed-loop systems from over-pressurization. The lead-free construction meets current federal and state potable water compliance standards. Licensed plumbers install this valve as a primary or supplemental safety device on water supply systems where pressure regulation and code-mandated relief protection are required.

This relief valve is suited for residential water heating systems, potable water supply lines, and light commercial plumbing applications where a compact 0.5-inch MPT connection is appropriate. It is typically installed on water heaters, expansion tanks, boilers, or inline on supply runs requiring pressure protection. The lead-free rating makes it acceptable for use on systems carrying drinking water under applicable plumbing codes.

Key Features

• Lead-free construction compliant with potable water standards
• 0.5-inch MPT connection for standard threaded pipe installation
• 75 psi factory-set relief pressure
• Compact design suitable for water heaters and supply line applications
• Automatic pressure relief helps protect plumbing systems from over-pressurization

Compatibility

Designed as an OEM-style replacement or new-installation pressure relief valve for residential and light commercial plumbing systems requiring a 0.5-inch MPT lead-free relief valve rated at 75 psi.

Installation Notes

A licensed plumber should install or replace pressure relief valves in accordance with local plumbing codes and the International Plumbing Code (IPC). Shut off the water supply and relieve system pressure before removing or installing this valve. Use thread sealant tape rated for potable water on all threaded connections. Never cap or plug the discharge port of a relief valve once installed.

Technical Specifications

• Connection Type: 0.5 inch MPT
• Relief Pressure: 75 psi
• Lead Free: Yes

Standard Information

• Brand: A.Y. MCDONALD
• Manufacturer Part Number: 5421-325