Allen-Bradley 849-ZOD331 Time Delay Relay

The Allen-Bradley 849‑ZOD331 Ser B is a pneumatic timing relay with an OFF‑DELAY function designed for 110–120 VAC control circuits that operate at 50/60 Hz. It is part of the 849 timing relay family, a class of industrial timers that uses a pneumatic mechanism to sustain output for a timed interval before release, which makes it suitable for sequencing, interlocks, and controlled de-energization in machinery such as conveyors, presses, and feeders. Verified distributor listings identify 849‑ZOD331 as a 110/120 VAC unit with Ser B designation; the model is documented as discontinued by the manufacturer, so compatibility with modern replacements should be checked. As with other 849 relays, the timing action is achieved via pneumatic means, distinguishing it from solid-state or electro-mechanical timers and aligning with older Rockwell control schemes used in legacy panels. Note that replacement options typically involve newer Allen-Bradley timing relays or equivalent 110/120 VAC OFF‑DELAY timers from other manufacturers.