The Xylem McDonnell & Miller RS-1-BR-1 Single Level Remote Sensor is a monitoring device designed to detect liquid levels in HVAC and boiler systems. It works by sensing the presence or absence of fluid at a designated point and sending a signal to the control system for appropriate action. Commonly used in boilers, condensate systems, and water management applications, it ensures accurate level monitoring. Its use enhances system safety, prevents equipment damage, and supports reliable and efficient operation.