Honeywell Pressuretrol Pressure Controller with additive differential, PA404A Model, 1/4 in Nominal, Female Pipe Thread Connection, Switching Action: Snap, SPST, 20 lb/sq-in, 0.5 - 9 lb/sq-in Operating, 1 - 5 lb/sq-in Adjustable Differential Pressure, 0.25 A at 0.25 to 12 VDC, 120 VAC, Resistive: 8.3 A, 240 VAC, Resistive: 8.3 A, 277 VAC, Resistive 7.2 A Contact, 150 deg F Maximum Ambient, 3-3/8 in W x 4-15/32 in H x 2-1/4 in D

• 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 levelContains an SPST Micro switch snap-acting switchSensitive pressure actuated diaphragm expands or contracts with pressure variations, moving a lever mechanism which operates the snap switchA screw on top of the case allows set point adjustment without removing the coverDifferential is adjusted by means of a dial located inside the caseRecommended minimum setpoint is differential setting plus 1-1/2 lb/sq-inStainless steel diaphragm sensor elementMakes at setpoint on pressure fall breaks at setpoint plus differential on pressure rise