Mueller Streamline a15503-400 Pressure Relief Valve 400 Psi

Product Description

The MUELLER STREAMLINE a15503-400 is a straight-through pressure relief valve designed to protect pressurized fluid systems from overpressure conditions. Set at 400 psi, it opens when line pressure reaches the preset threshold and reseats when pressure returns to a safe level. The brass body provides corrosion resistance in potable water and refrigerant-adjacent applications. At 0.35 pounds and 3 inches wide, this is a compact inline safety device. It is installed by licensed plumbers and HVAC technicians as a code-required safeguard in compressed-fluid lines, refrigeration circuits, and related pressure systems.

This valve is suited for residential and light commercial installations where a 3/8 x 1/2 inch NPTFE x flared connection is required. The NPTFE inlet threads to pipe fittings or manifold ports, while the flared outlet connects to standard tubing. Its operating pressure range of 150 to 700 psi and temperature rating of -40 to 300 degrees F make it compatible with a range of fluid and refrigerant service conditions. Plumbers and refrigeration technicians install this valve on pressurized lines requiring a dedicated relief path.

Key Features

• 400 psi factory pressure setting — opens on overpressure, reseats automatically
• Operating pressure range: 150 to 700 psi
• Temperature rated from -40 to 300 degrees F
• Brass body construction for corrosion resistance
• 3/8 x 1/2 inch NPTFE x flared end configuration for direct inline installation
• Compact 3-inch width and 0.35-pound weight for tight spaces

Compatibility

Designed as an OEM-style replacement or new-installation straight-through pressure relief valve for pressurized plumbing and refrigeration lines requiring a 3/8 x 1/2 inch NPTFE x flared connection.

Installation Notes

Installation must be performed by a licensed plumber or HVAC-refrigeration technician in accordance with applicable local codes and ASME or ASHRAE standards. Depressurize and isolate the system completely before removing or installing any pressure relief device. The relief outlet must be piped to a safe discharge location per code — never capped or plugged. Verify the valve pressure setting matches the rated working pressure of the system before installation.

Technical Specifications

• Pressure Setting: 400 psi
• Pressure Rating: 150 to 700 psi
• Temperature Rating: -40 to 300 degrees F
• End Type: NPTFE x Flared
• Nominal Size: 3/8 x 1/2 inches
• Width: 3 inches
• Body Material: Brass
• Weight: 0.35 pounds

Standard Information

• Brand: MUELLER STREAMLINE
• Manufacturer Part Number: a15503-400