Series-1950G

Supported Applications

The Dwyer Series 1950G is an explosion-proof differential pressure switch designed for monitoring air and compatible combustible gases. The series combines the functionality of the popular Series 1900 Pressure Switch with a compact, rain-tight housing suitable for outdoor installations. It is engineered for use in hazardous locations including Class I, Groups A*, B, C, D; Class II, Groups E, F, G; and Class III atmospheres.

Operating Conditions & Performance

The Series 1950G operates within an ambient temperature range of 0 to 140°F (-17 to 60°C). The unit is rated for a continuous pressure limit of 45 in w.c. (11.2 kPa) and can withstand surge pressures up to 10 psig (68.95 kPa). Six distinct operating ranges are available, covering set-points from 0.07 to 20 in w.c.

Performance specifications include the following approximate deadbands based on model range:

• 1950G-00-B: Range 0.07 to 0.15 in w.c.; Deadband at min set point: 0.04; Max set point: 0.06.
• 1950G-0-B: Range 0.15 to 0.5 in w.c.; Deadband at min set point: 0.06; Max set point: 0.11.
• 1950G-1-B: Range 0.4 to 1.6 in w.c.; Deadband at min set point: 0.11; Max set point: 0.29.
• 1950G-5-B: Range 1.4 to 5.5 in w.c.; Deadband at min set point: 0.4; Max set point: 0.9.
• 1950G-10-B: Range 3.0 to 11.0 in w.c.; Deadband at min set point: 0.9; Max set point: 1.8.
• 1950G-20-B: Range 4.0 to 20.0 in w.c.; Deadband at min set point: 1.2; Max set point: 3.0.

Note that switch capabilities may decrease with an increase in ambient temperature, load inductance, or cycling rate. Set point drift may occur with ambient temperature changes.

Configuration Options

The series is offered with multiple certification options and power configurations to meet regional safety standards and electrical requirements.

• Certifications: Units are available with UL, CSA, FM listings; ATEX compliance (II 2G Ex db IIB+H2 T6 Gb); IECEx certification (IECEx UL 19.0045X); UKCA Ex approval; China CCC; Korea KCs; and India PESO registration.
• Power Supply: Standard operation is on 24 VDC ±10%. Optional power supplies include 120 or 240 VAC ±10%.
• Output Signal: The switch provides a 1 Form C relay (SPDT) output. Electrical ratings are listed as 10 A, 120/240 VAC, 28 VDC resistive; and 50 mA, 125 VDC.
• Housing & Connections: The enclosure is constructed of anodized aluminum with a rating of IP54 (NEMA 3) and NEMA 7 and 9. Process connections are provided via two 1/8" female NPT ports for low and high pressure sensing. Electrical entry utilizes a 1/2" female NPT conduit connection.
• Dimensions: The unit measures approximately 5-7/16 in [138.1 mm] diameter with an overall height of 4-7/8 in [123.8 mm]. Weight is listed as 2 lb 15.7 oz (1.35 kg).

Key Product Differences

Variants within the Series 1950G are distinguished by their operating range, voltage selection, and certification suffix.

• Certification Suffixes: The model number includes a suffix to denote approval: "NA" indicates UL/CSA/FM approvals (not ATEX compliant); no suffix or specific codes indicate compliance with ATEX, IECEx, UKCA Ex, CCC, KCs, or PESO standards.
• Voltage Selection: The final digits of the model number specify voltage: "24" for 24 VDC, "120" for 120 VAC, and "240" for 240 VAC.
• Housing Access: A captive screw allows the top plate to swing aside while remaining attached, providing access to the internal terminal block without full disassembly. Set point adjustment is made via a screw type mechanism on top of the housing.