Barksdale D1H-H18 Pressure Vacuum Actuated Diaphragm Switch

The Barksdale D1H-H18 is a housed, diaphragm-style pressure/vacuum switch with a single SPDT contact and an adjustable setpoint of 0.4–18 psi (0.03–1.2 bar). It uses a 1/4" NPT female pressure port and is built around an anodized aluminum housing with a NEMA 4 enclosure for reliability in demanding environments, while wetted parts consist of 304 stainless steel and a 17-7PH stainless steel diaphragm. Electrical ratings on housed models are up to 10 A at 125/250 VAC and 3 A at 480 VAC, with optional UL approvals available. For wiring, housed units terminate via a 1/2" NPT conduit connection; stripped versions provide about 18 inches of free leads (approximately 18" long, #16 AWG). The D1H-H18’s designation reflects its dual actuation capability (pressure or vacuum) in a compact package, making it suitable for process control tasks where a fixed pressure threshold must trigger a relay or interlock in pneumatic systems such as compressors, vacuum pumps, or other industrial equipment.