Generally speaking, The Nanoject II assumes it is in the "home" position when the device is powered up. When unplugging the unit, make sure the plunger is in the home position.

To reset the plunger to the home position, push the fill button (to retract) or the empty button (to extend the plunger) while simultaneously holding the inject button. When the plunger reaches the home position, release both buttons and the unit will be reset.

Note: You can observe when the plunger is in the home position. The tip of the wire plunger will be slightly recessed from the end of the collet. (This position prevents accidental damage to the plunger when not in use.)