PSW-400

Supported Applications

The Omega PSW-400 Series consists of heavy-duty industrial pressure switches designed for hazardous atmospheres. These devices feature a dual-chamber design that isolates electronics from the process media, making them suitable for environments requiring NEMA 7 and 9 classifications (explosion-proof and dust-ignition proof). The series is certified by UL listed; Class I, Divisions 1 and 2, Groups B, C, D; Class II, Divisions 1 and 2, Groups E, F, G and CSA certified. Applications include monitoring pressure in systems ranging from vacuum to high-pressure industrial processes.

Operating Conditions & Performance

The PSW-400 Series covers a broad measurement envelope with adjustable ranges spanning Vacuum to 3000 psi. Specific standard unit ranges include -6 to -30 inHg vac, 6 to 30 inH2O, 12 to 60 inH2O, 30 to 150 inH2O, and pressure steps from 3 to 15 psi up through 600 to 3000 psi. Metric equivalents are available for all ranges (e.g., -20 to -100 kPa vacuum; 4.2 to 21 MPa high pressure). The series offers a repeatability of ±1% of range and features vibration-resistant setpoints.

Operating conditions support an ambient temperature from -29 to 65°C (-20 to 150°F) with the same limits for storage. Process temperatures depend on the diaphragm material: Stainless Steel supports up to 149°C (300°F), while Buna-N is rated to 65°C (150°F). Proof pressures vary by model, ranging from 20 psi for low-pressure inH2O models to 12,000 psi for the highest pressure ranges.

Configuration Options

The series is configurable across several dimensions including setpoint type, diaphragm material, and electrical output ratings. Key capabilities include:

• Setpoint Configuration: Available with single or dual SPDT switches. Dual-setpoint models (PSW-4xx) offer independently adjustable deadbands.
• Switch Ratings: Standard 10 A: 125/250 Vac for single setpoints; Two 15 A: 125/250 Vac switches for dual-setpoint models. Optional hermetically sealed 5 A: 125/250 Vac switches are available via the "-P" (single) or "-PP" (dual) options.
• Wetted Materials: Carbon steel is used for vacuum through inH2O ranges. Stainless Steel (316 SS) and Buna-N diaphragms are offered, with 316 SS required for oxygen service.
• Housing & Connections: The enclosure is a dual-chamber, epoxy-coated cast aluminum casting with gasketed seals. Electrical connections utilize two ea. ¾ NPT electrical conduit hubs. Process connections include ¼ FNPT (vacuum to 600 psi), ½ MNPT, and ¼ FNPT for 1000 to 3000 psi ranges.
• Special Options: Oxygen service is available by specifying option "-X6B" (oxygen cleaning) with extra cost on 316 SS models. A 316 SS Welded Pressure Activator (option "-S") is offered for 15 to 600 psi ranges.

Key Product Differences

The PSW-400 Series distinguishes itself through specific model numbering that indicates range and switch configuration. Models beginning with PSW-40x (e.g., PSW-401 to PSW-411) are single-setpoint switches featuring a 10 A SPDT output. Models in the PSW-42x series (PSW-421 to PSW-431) provide dual setpoints with two independently adjustable scales and Two 15 A SPDT outputs, offering fixed deadband configurations.

Additional variations include the PSW-44x family (e.g., PSW-445 through PSW-448), which also feature dual-setpoint capabilities but are configured with specific deadband ranges distinct from the standard 42x series. For example, while PSW-425 covers a range of 3 to 15 psi with a deadband of 0.5 to 1 psi, other models in this family may offer different adjustable spans within similar pressure bands.