Description

Overview

The PR-3 pressure protection valve manages air supply so auxiliary circuits only receive air after the primary reservoirs reach a safe pressure. As a result, the PR-3 pressure protection valve helps protect the service brake system on trailers and trucks during normal operation and unexpected leaks.

Features

• Firstly, the PR-3 pressure protection valve closes around 60psi to reserve air for the brake system when downstream circuits fail.
• Additionally, 1/4in NPT supply and delivery ports make plumbing into common heavy vehicle air layouts straightforward.
• Moreover, the compact body suits tight installation spaces on many trailer and truck chassis.
• Finally, the non adjustable design provides consistent closing behaviour once installed correctly.

Specifications and Materials

This PR-3 pressure protection valve is intended for heavy vehicle air brake systems where the main reservoirs must fill quickly before air flows to secondary or accessory circuits. Therefore, it acts as a normally closed valve that opens only after system pressure reaches the specified level.

Supply port: 1/4in NPT. Delivery port: 1/4in NPT. Closing pressure: nominal 60psi, non adjustable. Operating use suits PR-3 style reservoir control layouts used with trailer and truck spring brake systems.

Part number: AB8503.

For detailed maintenance and testing procedures on PR series valves, refer to this manufacturer technical guide

Compatibility and Fitment

This cross-reference listing means this valve is a suitable replacement for the part numbers and applications shown. Some changes in air line plumbing may be required. 286460, PR3.

Compliance and Safety

Before any work starts, park the vehicle securely, apply the park brake and chock the wheels, then drain all air reservoirs so the system depressurises. Next, technicians should follow the vehicle air system schematic, mark each air line, and connect the supply and delivery ports to the correct circuits.

After installation, they must pressure test the system, verify that the valve closes at the expected pressure, and check all joints for leakage with an approved leak-detection solution. Consequently, the main brake reservoirs keep priority and the heavy vehicle remains compliant with workshop safety expectations.

Trailer Applications

This valve suits on highway trailers and rigid vehicles where accessory circuits such as suspension, auxiliary tanks or ancillary equipment must not rob pressure from the primary brake system. In addition, workshops can use the PR-3 pressure protection valve during brake refits, trailer upgrades or air system repairs that call for a non adjustable 60psi protection valve.

Cross-reference and Suitability

This part cross-references to or suits the following equivalent part numbers and compatible alternatives:

Why Choose ICS Trailers

ICS Trailers focuses on proven heavy vehicle components and backs them with practical support for workshops and fleet operators. Furthermore, you get clear technical information, competitive pricing and access to a wide range of compatible air brake parts from one supplier.

For more air brake components suited to similar systems, browse our Air Brake Parts range at ICS Trailers