Rheem-Ruud AP17940-1 Condensate Water Sensor is a monitoring component designed for compatible Rheem-Ruud air conditioning and heat pump systems. It detects the presence or level of condensate water in the drain pan or condensate management area and provides a signal to the HVAC control system when abnormal water accumulation occurs. Used with indoor air handlers and cooling equipment... https://www.partshnc.com/rheem-ruud-ap17940-1-condensate-water-sensor