Fisher Size 30 Spring-Opposed Diaphragm Actuator | 3/4" Travel | 3–15 PSI Range

What pressure, flow and temperature is it rated for?

This actuator operates on a 3–15 PSI instrument air supply. Diaphragm actuators do not contact process media and are not rated for process pressure or temperature—those ratings depend on the valve body they're mounted to. Flow capacity is determined by the valve trim, not the actuator.

What gases is it compatible with, and has it been oxygen cleaned?

Diaphragm actuators use instrument air or inert gas to position the valve stem and do not contact process media, so process gas compatibility is not applicable. The listing does not indicate oxygen cleaning of the instrument air side. If you're using the actuator in oxygen service, confirm with the seller whether it has been cleaned and whether documentation is available.

What materials are the wetted parts?

The actuator itself does not have wetted parts in contact with process fluids. Fisher Size 30 actuators typically use a molded diaphragm (often nitrile or other elastomer) exposed to instrument air, with a steel or aluminum casing. Contact the seller for specific diaphragm material and casing construction on this unit.

What should I inspect before putting it into service?

The listing states this unit requires re-certification before use. Inspect the diaphragm for cracks, hardening, or permeation damage, and verify the spring provides consistent force across the travel range. Check stem packing for leaks, confirm travel stops at 3/4" with a gauge block, and bench-test response at 3, 9, and 15 PSI to verify linearity and absence of hysteresis or stiction.