I have a 50 pint dehumidifier model #SGDEH 50-2 and read the directions to set the humidity level and the unit will shut off. I've set it at 65 and thought it would shut off when this 65 is shown but continues to run. What number is best to set at to get the most efficiency? I've misplaced my instruction booklet and tried to get one online but my model is not listed.