PSW-100

Supported Applications

The Omega PSW-100 Series consists of general purpose industrial pressure switches designed to convert a pressure signal into an electrical signal. The series utilizes bellows, diaphragm, or piston sensors that respond to pressure changes and actuate a single snap-acting switch at a pre-determined set point. Control set points are varied by turning the internal adjustment hex.

Operating Conditions & Performance

The PSW-100 Series covers measurement ranges from 0.5 inH2O to 3000 psi, with a pressure rating of Vacuum to 3000 psi. Setpoint repeatability is ±1% of the adjustable range for most models; however, models PSW-118 through PSW-125 and PSW-132 through PSW-133 offer ±1.5%. The series maintains setpoint stability after shock events up to 15 g (10 ms duration) and vibration levels of 2.5 g at frequencies from 5 to 500 Hz.

Ambient temperature limits are -40 to 70°C (-40 to 158°F), with an exception for models PSW-107 through PSW-117 and PSW-134 through PSW-139, which operate from -20 to 70°C (-4 to 158°F). Storage temperature is rated at -55 to 70°C (-67 to 158°F).

Process temperature limits depend on the wetted material:

• Buna-N: -25 to 95°C (-13 to 203°F)
• Phosphor Bronze: -40 to 150°C (-40 to 302°F)
• Stainless Steel: -55 to 205°C (-67 to 401°F)

The enclosure is rated NEMA 4X (IP66). A note in the documentation states that switching may not be accurate in the lower and upper 10% of the range, recommending operation within the middle 80% of the adjustable range.

Configuration Options

The series is offered with various sensor elements, wetted materials, process connections, and switch configurations to accommodate different pressure ranges and media requirements. The enclosure is constructed from die-cast aluminum (max 0.6% copper) with an epoxy-coated blue finish.

Sensor Elements & Wetted Materials

• Buna-N Diaphragm: Used in models PSW-107 through PSW-117 and PSW-134 through PSW-139. Includes Buna-N O-rings.
• Stainless Steel (SS) Diaphragm: 316 SS diaphragms are used in models PSW-104, PSW-105, and PSW-118 through PSW-125. Includes a ¼ FNPT pressure connection.
• Phosphor Bronze Bellows: Used in models PSW-127 through PSW-129 with brass pressure connections.
• Stainless Steel (SS) Bellows: 316 SS bellows are used in models PSW-130, PSW-131, and PSW-132. Includes a ¼ FNPT pressure connection.
• Piston Sensor: Model PSW-133 utilizes a 303 SS piston with Buna-N O-ring and ¼ FNPT SS pressure connection for ranges up to 3000 psi.

Process Connections & Electrical Ratings

Pressure connections are typically ¼ FNPT, though specific models may vary. The electrical output is one SPDT or DPDT switch that can be wired 'normally open' or 'normally closed'. Standard ratings include:

• SPDT Switches: 15 A at 125/250/480 Vac resistive.
• DPDT Switches (e.g., PSW-110, PSW-128): 10 A rating.
• External Manual Reset: Available on select models with a 15 A at 125/250 Vac resistive rating.

The enclosure features a ½ NPT conduit connection and two ¼" diameter knockouts. The unit weighs approximately 0.9 kg (2 lb).

Key Product Differences

Variants within the PSW-100 Series are distinguished by their sensor technology, adjustable range, deadband characteristics, and switch type.

• Buna-N Diaphragm Models (PSW-107 to PSW-117): Cover ranges from 1.5 psi to 1000 psi with nickel-plated brass or aluminum pressure connections depending on the specific model group.
• Vacuum and Low Pressure Models: The Buna-N diaphragm series includes models PSW-134 through PSW-139, covering vacuum ranges from 300 inWC vac to positive pressures up to 250 inWC. These utilize aluminum pressure connections.
• Stainless Steel Diaphragm Models (PSW-104, PSW-105, PSW-118–PSW-125): Designed for ranges from 1 psi to 1700 psi. Some models in this group offer adjustable deadband or external manual reset options.
• Bellows Models: Phosphor bronze bellows (PSW-127–PSW-129) and stainless steel bellows (PSW-130–PSW-132) handle vacuum to 500 psi ranges. PSW-128 offers a DPDT switch option.
• High Pressure Piston Model: The PSW-133 is the only model in this series utilizing a piston sensor, covering 125 to 3000 psi with a proof pressure of 10000 psi.