A refrigerator ice maker has a valve that fills a tray with water until it’s frozen, at which point a set of pins sweep the ice out of the mold and down a shoot into the bin. Find out how an ice maker when knows when it’s full with help from a home remodeling specialist in this free video on ice makers. Expert: William Perkinson Bio: William Perkinson is a partner with Perkinson Building Corporation, based in Birmingham, Ala. Filmmaker: Tim Brown