Xylem 157S-MD Low Water Cut-Off and Pump Controller with Maximum Differential

The Xylem 157S-MD is a combination low water cut-off and pump controller designed for commercial and industrial steam boiler applications. This float-type control features maximum differential operation to prevent nuisance burner shutdowns in low pressure applications, making it ideal for boilers of any steaming capacity.

Key Features:

• Snap acting SPDT switch for reliable high-temperature service
• Single pole, single throw switch for pump control
• Single pole, double throw switch for low water cut-off and alarm actuation
• Monel bellows construction provides superior corrosion resistance
• Maximum differential operation prevents false shutdowns
• Maximum operating pressure: 150 PSI (10.5 kg/cm²)
• Screwed connection type for standard installation

The 157S-MD automatically monitors water levels in steam boilers and activates the pump when water drops below safe operating levels. The low water cut-off function shuts down the burner if water levels become critically low, protecting the boiler from dangerous dry-fire conditions. The maximum differential feature ensures consistent operation even during pressure fluctuations common in low-pressure heating systems.