How it Works
The Liquid Level Switches use light reflecting from a conical glass prism as a
means of detecting the absence of a fluid at the level of the glass cone.
When no fluid covers the lower half of the cone, infrared light from the
module reflects from the mirror-like inner surface of the cone back to a light
detector signaling the electric module to switch. When fluid covers the lower
half of the glass cone, the light from the module passes into the fluid. This
absence of light is detected by the module which switches into the opposite direction.