Calibrating the Z Axis
Calibrating the Z axis is one of the best ways to ensure a perfect print every time. With good quality filament, a level bed, and a properly calibrated Z axis you can expect great printing results. Of these tasks, the one you should do the most is check the Z axis calibration. We suggest you do a Z calibration when you use your machine after its been sitting for more than a week or so since the last print or at least once a week if you use the Monolith regularly.
Click the Home All button located on the Print Panel of Repetier. The Monolith will move the XY position to the front-left position on the bed. Then the Z axis will move down into position on the glass. Slip a regular piece of paper (you can find some pre-cut sheets in your tool bag) between the nozzle and the glass bed. It should just barely be able to fit. If not, move the Z axis adjustment screw located to the left side of the bed. Turning the screw clockwise will raise the nozzle stop and counter-clockwise will lower it closer to the bed.
Click the Home All button and try to slip the paper under the nozzle again. It may take several attempts to get it just right. You are looking for the paper to fit snugly under the nozzle, but still be able to move.