Removed collar from supply trunk for vent going into office room. Screwed in sheet metal over hole on ductwork. Mastik sealant over sheetmetal after screwing onto ductwork. Placed insulation over repair and taped insulation over sheetmetal. Took pictures. Customer wanted me to switch fan speed from medium too low, system is strictly ac no furnace attempted to put on low and unit began to freeze over. Informed customer medium is as low as you can go for a/c or else unit freezes over.