The McDonnell & Miller Model 150Sis a mechanical float-type ON/OFF level controller and low water cut-off. The controller is piped into an external water column via 1” NPT equalizing pipes. The 150S is typically used to control a two-position makeup valve. When used on a boiler, the controller also includes a single pole double throw (SPDT) switch for low water cutoff and alarm. The 150S is rated for a maximum pressure of 150 PSI. A single McDonnell & Miller 150S is commonly paired with an electronictwo position makeup valve for ON/OFF operation. The snap action switches have a 3/4" fixed control range. That is, the makeup valve will open when the level is 5/8” above the “Cut-off line” and the valve will close when level is 1-3/8” above the “Cut-off line”. This type of control is common for applications where maintaining a steady flow into the tanks is not required, for example, small atmospheric feed tanks (less than 500 gallons). For larger atmospheric tanks and deaerators, a modulation makeup valve is typically used for more precise control.

• ON/OFF level controller
• Maximum Operating Pressure: 150 PSI
• Connects to tank via 1” NPT equalizing pipes
• Includes cast iron float housing
• 3/4” differential control range for pump control
• 7/8” differential control range for burner control (when used on boiler)
• 2 precisionsnap action switches
• 1 SPST switch for pump control, 7.4 amps at 120VAC (3.7 amps at 240 VAC)
• 1 SPDT switch for burner control and alarm, 1 amp at 120 VAC (0.5 amps at 240 VAC)