PSW-700

Supported Applications

The Omega PSW-700 Series consists of heavy-duty industrial pressure switches designed for rugged environments requiring hazardous location approvals. These units are actuated by bellows, diaphragm, or piston sensors that respond to pressure changes to activate SPDT or dual SPDT snap-acting microswitches. The series is suitable for use in Class I, Divisions 1 & 2, Groups B, C, and D; Class II, Divisions 1 & 2, Groups E, F, and G; Class III; or non-hazardous locations only.

Operating Conditions & Performance

The PSW-700 series covers a broad measurement envelope ranging from vacuum to high pressure. Standard ranges include -300 to 0 inH2O, 30 inHg Vacuum to 3000 psi, and specific spans such as 5 to 30 psi up to 80 to 1700 psi depending on the model. Proof pressure ratings vary by range from 100 psi for low-pressure models (e.g., PSW-721) to 10,000 psi for high-range units like the PSW-710.

Performance specifications include a repeatability of ±1% range. The series maintains setpoint stability after shock events up to 15 g (15 ms duration) and vibration at 2.5 g from 5 to 500 Hz. Ambient operating temperatures are rated -50 to 71°C (-58 to 160°F), with the exception of models PSW-703 through PSW-705, which operate between -18 to 71°C (0 to 160°F). Process temperature limits depend on wetted materials: stainless steel supports -57 to 204°C (-70 to 400°F), brass supports -40 to 149°C (-40 to 300°F), and Buna-N supports -23 to 93°C (-10 to 200°F).

Configuration Options

The series offers configurable setpoint adjustment methods, electrical outputs, and wetted materials tailored to specific process needs.

• Housing & Enclosure: Low copper-cast epoxy-coated aluminum with NEMA 4X, 7, 9 (IP66) ratings. Electrical connections are provided via two ¾" NPT conduit openings; an explosion-proof plug is included for the unused opening.
• Setpoint Adjustment: Models PSW-701 through PSW-717 feature external knob and pointer adjustment with dial graduations visible on the face. Models PSW-721 through PSW-735 utilize internal set point adjustment via a hex tool (blind adj).
• Sensor Elements & Wetted Materials: Options include welded 316L SS diaphragms, sealed brass bellows, welded 316 SS bellows, Buna-N O-rings with stainless steel pistons, and Buna-N diaphragms. Process connections are available in ¼" NPT or ½" NPT.
• Electrical Output: Switches provide either a single SPDT microswitch (15 A at 125/250/480 Vac) or dual SPDT configurations. Accessories such as audible alarms and relay modules are available online.

Key Product Differences

The PSW-700 series is divided into distinct model families based on adjustment method, pressure range, and sensor technology:

• External Adjustment (PSW-701 to 717): These models feature a visible dial with graduations for setpoint indication. They cover ranges from vacuum (-30 inHg) up to 3000 psi and typically utilize dual SPDT microswitches.
• Internal Adjustment (PSW-721 to 735): Designed for tamper-resistant applications, these models lack external dials. They cover differential low-pressure ranges in inches of water (-300 to 0 inH2O) and higher pressure spans up to 80 to 1700 psi.
• Sensor Construction: Low-range units (e.g., PSW-721–726, -50 to 50 inH2O ranges) often employ diaphragm or bellows sensors with Buna-N components. Higher pressure models utilize stainless steel pistons and welded SS bellows.
• Dimensions: Overall dimensions vary by model family; for example, PSW-701–717 units range from 8.09 to 8.75 inches in height (Dimension A), while internal adjustment models like the PSW-721–735 measure up to 8.84 inches.