Series H2 Dual-Action Explosion-Proof Pressure Switch

Brand: Dwyer Instruments, LLC

The Dwyer Series H2 is designed for sequencing two different actions as pressure of a liquid or gas increases or decreases.

Explosion-proof, UL & CSA Listed for Class I, Groups B, C & D and Class II, Groups E, F & G.

The design consists of two concentric pistons operated by a single diaphragm with one pressure chamber. Each piston actuates a separate switch independent of the other. 

The switches may be adjusted to operate together, at opposite ends of the range or at two intermediate set points. The threaded top is removed to field adjust or service switches without disturbing electrical or pressure connections.

The Duotect® switch is explosion-proof and weatherproof. It can be mounted in any position and is not affected by vibration.
  • Explosion-proof and weatherproof housing provides device protection for outdoor use or harsh environment operation
  • UL listed, CSA approved to support rigorous process applications and regulations
  • Independent piston action design for either gas or liquid allows switches to active together or independently based on settings
  • Mounting in any position and not affected by vibration provides reliable switching for equipment


Adjustment Type

  • Internal Nut

Approvals & Certifications

  • CSA
  • UL

Conduit Connection

  • 3/4” NPT Female

Diaphragm Material

  • FEP

Electrical Connectors

  • 18 AWG, 18” (460 mm) Long

Electrical Rating

  • 5 A at 125/250 Vac
  • 5 A Resistive, 3 A Inductive at 30 Vdc

Enclosure, Body Material

  • 316 Stainless Steel

Environmental Protection

  • IP66
  • NEMA 4X

Mounting Position

  • Any Orientation

NPT Connection

  • 1/4” NPT Female

O-Ring Material

  • Buna-N

Set Point - Decreasing

  • bar: 0.207 to 68.95
  • kPa: 21 to 6,895
  • psig: 3 to 1,000

Set Point - Increasing

  • bar: 0.345 to 103
  • kPa: 34.47 to 10,300
  • psig: 5 to 1,500

Switch Type

  • Two SPDT Snap Switches

System Pressure

  • bar: 103.4
  • kPa: 10,342
  • psig: 1,500

Temperature Range

  • -20° to 135° C (-4° to 275° F) CSA Approved: -20° to 90° C (-4° to 184° F)

  • Mechanical HVAC or Process Equipment
  • Chemical, Petroleum, Food and Drug Processing Industries
  • Process and Industrial Applications
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