Key Features and Functions:Prevent Backflow: It secures the pressurized air within the tank, preventing it from returning to the cylinder, which could cause a, or "stuck," compressor motor upon restart.Operating Mechanism: Typically spring-loaded, the valve features a ball or disc that is forced open by the pressure of air flowing in the "allowed" direction. When the compressor stops, pressure from the tank pushes the disc back onto its seat, ensuring a sealed, one-way system.Types & Materials: Common types include male-threaded, inline, one-way, and three-way, often constructed from brass for durability.Symptoms of Failure: If your compressor leaks air from the intake filter when turned off, or if the motor fails to start, the non-return valve is often stuck or damaged