Automatic fire suppression systems normally utilize two pumps. One unit is the main fire pump which delivers large volumes of water to the fire suppression system (sprinklers) in case of fire. When there is no fire, a low flow, high head “Jockey Pump” is used to overcome the normal system plumbing leakage that bleeds down system pressure over time, and maintains a consistent system pressure. When the system bleeds enough pressure to trigger the jockey pump, it cycles on and re-pressurizes the system back to its normal level. When a large enough pressure drop occurs that the jockey pump cannot overcome it (such as a fire opening a sprinkler head or a fire hose being turned on), the main high volume fire pump starts and takes over the water supply duties. Utilizing the main fire pump for the re-pressurizing function would be very expensive and limit the life of the pump and motor due to the numerous starts & stops. A variety of different MTH turbines are used as fire system jockey pumps depending upon system size. See our Jockey Pump Selection Chart at https://www.mthpumps.com/applications/jockey.html to find the right size pump for your system.