The Allen-Bradley 849-ZAB32 Pneumatic Timing Relay from the 849 Timing Relays series uses an electrical impulse to drive the action of an electrical circuit with a built-in time delay whose duration is user-configurable. The circuit activation is achieved by an action between a pneumatic set of bellows which is filled with the incoming pressure signal and the electrical contact driver. A screw-type calibration needle valve is used to determine the speed at which the bellows will be completely filled, and that is the moment when the Allen-Bradley 849-ZAB32 Pneumatic Timing Relay will effectively change the status of its electrical connections from “on” to “off.” An important consideration that must be taken into account in this process is the device’s mounting position,because it can only be installed vertically with the coil on top.

The Allen-Bradley 849-ZAB32 Pneumatic Timing Relay offers a user-configurable delay time setting anywhere between 0.05 seconds and 180 seconds. This delay time is calibrated by turning the shaft of a needle valve that is constructed in the form of a screw up or down. The Allen-Bradley 849-ZAB32 Pneumatic Timing Relay is able to withstand a continuous carrying current between its contacts of 10 Amps. Its recommended operating temperature range is from 0 to 104 degrees Fahrenheit (-17.7 to 40 degrees Celsius) as long as there is no water in contact with the bellows mechanism. Only properly trained technicians, preferably with working experience and professional knowledge of pneumatic timers, should be tasked with the maintenance or repair of the relay. The electrical contact block can be replaced when it is damaged, and additional contacts or auxiliary contacts can be added if more circuits need to be connected to the pneumatic timing relay.