Masoneilan 3" Model 88U-25125 Diaphragm Control Valve | 1" Body | 300 ANSI | SVI-2 Valve Positioner | Air Filter Regulator

What pressure, flow and temperature is it rated for?

This valve is rated for 300 ANSI pressure service with a 1" body size. Flow capacity and temperature range are not specified in the listing—you'll need to request the trim designation, Cv value, and nameplate temperature limits from the seller to verify suitability for your process conditions. Diaphragm control valves in this class are typically limited to approximately 250°F due to elastomer constraints, but the actual rating depends on diaphragm material and spring selection.

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

Gas compatibility depends on the diaphragm material and trim configuration, which are not specified in the listing. There is no mention of oxygen cleaning or oxygen service preparation. If you require oxygen service, you must verify with the seller that the unit can be properly cleaned and that elastomers are oxygen-compatible—never assume a used valve is oxygen-safe without documentation and appropriate preparation.

What materials are the wetted parts?

The body material is 316 SS. The listing does not specify trim material (plug, seat, cage), diaphragm material, or spring material—request this information from the seller along with the full trim designation. On Masoneilan 88 series valves, common trim options include 316 SS, alloy 6, and hardened stainless, while diaphragms are typically Buna-N, EPDM, Viton, or PTFE depending on service.

What should I inspect before putting it into service?

The listing states this unit requires re-service before use. At minimum, inspect the diaphragm for cracks or hardening, verify seat and plug condition for wear or scoring, check all fasteners for corrosion, test positioner calibration and air supply integrity, and confirm spring tension. Bench test for stroking smoothness and seat shutoff, then perform loop testing with your control system before installing in-line—diaphragm control valves often develop hysteresis or dead band after storage that only shows up under signal.