Lennox AC repair. Upon arrival outdoor unit would not run when given a call for cooling. High pressure switch was tripped. Cleaned outdoor coil as it was the cause of the high pressure switch cutting out. Refrigerant levels are on the lower end, not yet low enough to freeze up the indoor coil but could be a problem in the next year or two. AC is about 17 years old and reaching the end of its life. Recommend starting to think about replacing in the next year or two