McDonnell & Miller model number 159S is a combination float-operated low water cut-off and pump controller for steam boilers with a separate water column. This control features an automatic reset with two 120 volt bi-metal snap switches. One switch is single pole, single throw for pump control. The other is single pole, double throw for low water cut-off and alarm actuation. Its maximum pressure is 150 psi and it has a tapped 1" FIP connection.
McDonnell & Miller, a Xylem brand, is a leader in engineering and manufacturing boiler and liquid level controls, low-water cutoffs, and flow switches for steam and hot water boilers in industrial, commercial, and building applications.