McDonnell & Miller 157S Boiler Low Water Cut-Off/Pump Controller

The McDonnell & Miller 157S Boiler Low Water Cut-Off/Pump Controller is a float-type boiler control that combines a reliable low water cutoff with a pump controller for safe boiler operation. This essential device protects equipment by automatically detecting low water and triggering an alarm or control action when levels fall.

Designed for use across residential, commercial, and industrial boiler systems, the 157S handles steam and water media and includes a water column for precise sensing. Key specifications ensure compatibility with standard power and connection requirements while delivering dependable protection.

• Port Connection: 1 Inch BSPT x 1 Inch BSPT
• Actuation Type: Alarm/Mechanical
• Switch Type: SPST/SPDT Snap Action
• Dimensions: 13-3/8" L x 16" H
• Current Rating: 7.4 A @ 120 V / 3.7 A @ 240 V (full load); 44.4 A @ 120 V / 22.2 A @ 240 V (locked rotor); 1 A @ 120 V / 0.5 A @ 240 V (alarm circuit)
• Input Supply Rating: 120/240 V AC, 345 VA
• Pressure Rating: 150 PSI
• Media Handled: Steam, Water
• Inclusions: Water Column
• Applications: Residential, Commercial, Industrial
• Standards: UL, CSA, FM