At what PSI should an air brake vehicle's air compressor start pumping?

The air compressor in an air brake system is designed to start pumping air when the system pressure drops to a certain level. For most heavy-duty vehicles equipped with air brakes, this threshold is typically set at 100 PSI. When the pressure within the air tanks falls to 100 PSI, the air compressor automatically engages to replenish the air supply. This is crucial for ensuring that there is enough air pressure available to operate the brakes effectively and maintain vehicle safety.

Maintaining adequate air pressure is vital since insufficient pressure can lead to brake failure or reduced braking efficiency. Therefore, the 100 PSI level serves as a critical point in the operation of air brake systems, helping to ensure that the system remains functional and safe during operation.