Abstract: An apparatus for automatically closing a shutdown seal on an open-drive centrifugal compressor to prevent the loss of refrigerant and damage to the seal, including a seal housing encompassing a rotor shaft, containing a shutdown seal and a running seal; the rotor shaft driven by a motor and axially moveable between the shutdown and running position, the shutdown position illustrated by the shutdown seal in the closed position and the running seal in the open position, the running position illustrated by the shutdown seal in the open position and the running seal in the closed position; a pressurized oil supply to move the shaft between the shutdown and running positions; a first sensor to determine when the motor is operating; a second sensor to measure the oil pressure; a solenoid controlling a release valve to remove pressure from the oil supply to move the shaft from the running position to the shutdown position once the motor has been inoperative for a given period of time and the oil pressure has fallen