Grundfos large UPS is a canned rotor, centrifugal pump for circulating water in heating systems and smaller air conditioner systems in commercial buildings. These pumps are based on glandless pump or canned rotor technology. The pumped liquid cools and lubricates the motor and rotating parts. Large UPS circulators are typically used in commercial building like schools, hospitals and office buildings for circulating domestic hot water, heating water and air conditioning fluid. The name UPS stands for the German Umwelts Pumpen Selektra, directly translated as circulator pumps selective. S for Selektra indicates that you can select between three speed settings.