Demand switch models operate only when liquid flow is required. Pump and motor stop instantly when discharge is closed. Diaphragm design eliminates troublesome shaft seal. Pump can be run indefinitely without damage. Ball bearing drive assures longer pump life. Excellent self priming capability. Santoprene diaphragms and viton valves are standard. Maximum temperature of pumped liquid 54 celcius. Permanent magnet motor with long life brushes. Fuse protected. Built in cooling fan.