Abstract: A method for testing a rotary atomizer valve using a system having a test device housing, a linear potentiometer including a resistive circuit and a movable shaft, and a controller includes, (a) with the shaft contacting a movable surface of the valve, obtaining a first reference data point representing a first position of the movable surface, (b) commanding an actuator to displace the movable surface in a first direction, (c) obtaining a first current data point representing a second position of the movable surface, (d) determining whether the second position equals the first position, (e) if not, setting the first current data point as the first reference data point and repeating steps (c) and (d), and (f) if so, recording the second position as a first end point of the valve.