Series H2 Dual-Action Explosion-Proof Pressure Switches Explosion-proof and weatherproof housing. Explosion-Proof, U.L. & CSA Listed for Class I, Groups B, C & D and Class II, Groups E, F & G. The H2 is designed for sequencing two different actions as pressure of a liquid or gas increases or decreases. The patented 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 Duotest switch is explosion-proof and weatherproof. It can be mounted in any position and is not attached by vibration. PHYSICAL DATA Temperature Limits:   275°F Pressure Connection:   1500 psig. Test pressure 6000 psig. Electrical Rating, Switches:   5 amps, 125/250VAC, 60 Hz. Two SPDT switches Wire:   18 gauge leads, 18" long Conduit connection:   ¾" NPT female Housing:   Machined aluminum satin finish Wetted parts:   Aluminum standard. Brass or stainless steel optional extra Diaphragm:   Mylar standard. Teflon optional O-ring:   Buna-N standard, Viton or Ethylene Propylene optional RANGES Model Number Low Range psig (bar) High Range psig (bar) H2A-1 H2A-2 H2A-3 3-40 (0.21-2.76) 25-250 (1.72-17.2) 100-1000 (6.89-68.9) 5-75 (0.35-5.17) 3-400 (2.07-27.6) 150-1500 (10.3-103) SUGGESTED SPECIFICATIONS Explosion-proof pressure switches shall be diaphragm operated to actuate two single pole double throw micro snap switches. Motion of each switch actuating piston shall be restrained by a spring that can be adjusted to set the exact pressure at which the switch will be actuated. Motion of the diaphragm shall be transmitted to each switch sequentially through concentric pistons. Switches shall be W.E. Anderson Catalog No. H2, Range No. ___ for the required operating ranges