HONEYWELL PA404A1033 Pressuretrol Controller with Additive: 1 psi to 5 psi Differential pressure and Breaks at setpoint on pressure fall; Spst makes at set point plus differential on pressure rise.. 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.
• 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.