McDonnell & Miller model number 157SRBP-MD is a combination float-operated low water cut-off and pump controller for steam boilers with an integral water column. The controller has 1/2" NPT tappings for gauge glass and tri-cocks. This control features an automatic reset with two 120 volt bi-metal snap switches plus two conductive probes for additional levels. 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 an alternative tapped 1-1/4" 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.