McDonnell & Miller model number 157S-RM 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 a manual 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 an alternative 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.