McDonnell & Miller 171702 150S Low Water Cut-Off/Pump Controller
McDonnell & Miller model number 150S is a combination float-operated low water cut-off and pump controller with maximum differential operation, which prevents nuisance burner shut-down in low pressure applications, 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.