The rotary valve is a critical component in many DeVilbiss oxygen concentrators, directing the flow of air through the PSA system. A dirty or malfunctioning valve can lead to purity issues, pressure alarms, and overall system failure. This guide offers a step-by-step process for biomedical technicians to correctly disassemble, clean, and reassemble a DeVilbiss rotary valve (part number 515A-702).