Allen-Bradley 849 ZOD321 Pneumatic Timing Relay

Allen-Bradley 849-ZOD321 Pneumatic Timing Relay delivers a precise time-delay control in industrial circuits using a pneumatic bellows timing mechanism. This model is part of the 849 family and accepts a 120 VAC coil while operating on standard 50/60 Hz power, aligning with common plant electrical systems. On the load side, the solid contacts are rated to switch up to 600 VAC, making it suitable for sequencing, start/stop logic, and interlocking tasks that drive motors, valves, or other actuators. Timing is achieved pneumatically rather than electronically, with silicon bellows designed to withstand a wide operating temperature range and provide reliable delay performance under industrial conditions. In typical installations, energizing the coil initiates the timing interval; the relay output changes state after the programmed delay, enabling simple, rugged control of downstream equipment. The 849-ZOD321’s compact form and robust construction suit panel- or cabinet-mounted applications in manufacturing or process environments where a durable, non-solid-state timer is advantageous.