Pressuretrol Controller w/ Subtractive: 1 psi to 5 psi Differential Pressure, PA404A1025

Overview: The PA404 is a series 40 (2-wire, SPST) pressuretrol controller for use in 24, 120, 240 or 277 volt control circuits or in self powered (millivoltage) applications. Features: 3-15 Psi Adjustable Pressure Range The PA404A is a pressure actuated high limit, safety control for steam heating boilers; it breaks an electrical circuit to shut down the burner if steam pressure rises above a safe level. The PA404B is used with suspension-type unit heaters to make the fan circuit when a pressure rise indicates the presence of steam. Each model contains an SPST MICRO SWITCH snap-acting switch. Sensitive pressure-actuated diaphragm expands or contracts with pressure variations, moving a lever mechanism which operates the snap switch. A screw on top of the case allows set point adjustment without removing the cover. Differential is adjusted by means of a dial located inside the case.