DWYER Series H2 Dual-Action Explosion-proof Pressure Switches

RM 0.00



Series H2 Dual-Action Explosion-proof Pressure Switches

Explosion-proof and Weatherproof Enclosure

Explosion-Proof, UL & CSA Listed for Class I, Groups B, C & D and Class II, Groups E, F & G. The Series H2 Dual-Action Explosion-Proof Pressure Switch is designed for sequencing two different actions as pressure of a liquid or gas increases or decreases. 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.


Product Applications

  • Mechanical HVAC or process equipment
  • Chemical, petroleum, food and drug processing industries
  • Process and Industrial applications



  • 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



  • Wetted Materials: 316 SS chamber with FEP diaphragm and Buna-N O-ring standard. Fluoroelastomer or EPDM O-ring optional.
  • Temperature Limit: 275°F (135°C). CSA approved: -20 to 90°C (-4 to 184°F).
  • Pressure Limit: 1500 psig (103 bar).
  • Enclosure Rating: UL listed explosion-proof, Class I, Groups B, C, and D. Class II Groups E, F, and G. Meets NEMA 4X (IP66). CSA optional. Class I, Groups B, C & D. Class II, Groups E, F, & G -20°C ≤ Tamb ≤ 75°C T6 [optional -20°C ≤ Tamb ≤ 40°C T5] Type 4.
  • Switch Type: Two SPDT snap switches.
  • Electrical Rating: 5 A @ 125/250 VAC, 5 A res., 3 A ind. @ 30 VDC. Gold contacts optional.
  • Electrical Connections: 18 AWG, 18″ (460 mm) long.
  • Conduit Connection: 3/4″ female NPT.
  • Process Connection: 1/4″ female NPT.
  • Mounting Orientation: Any position.
  • Set Point Adjustment: Internal nut.
  • Weight: 2 lb (.9 kg).
  • Deadband: Approximately 10% of range.
  • Agency Approvals: CSA, UL.


Models & Ordering

Model Description
H2S-1 Duotect® dual-action explosion-proof pressure switch, 3-40 psig (0.21-2.76 bar) low range, 5-75 psig (0.35-5.17 bar) high range
H2S-2 Duotect® dual-action explosion-proof pressure switch, 25-250 psig (1.72-17.2 bar) low range, 30-400 psig (2.07-27.6 bar) high range
H2S-3 Duotect® dual-action explosion-proof pressure switch, 100-1000 psig (6.89-68.9 bar) low range, 150-1500 psig (10.3-103 bar) high range


Additional information


H2S-1, H2S-2, H2S-3