A pump system features a power adapter and a pump having a signal processor. The power adapter includes voltage settings that respond to a voltage setting by a user and provide a selected voltage. The signal processor receives signaling containing information about the selected voltage supplied to a motor to run the pump, and also containing information about whether a current draw of the pump is lower than a predetermined low current level or is higher than a predetermined high current level; and determines whether to shut off the pump after a predetermined time, based on the signaling received.