Continuous flow dryers may be operated at temperatures up to about 200 F. Temperatures over 110 F should not be used to dry sunflower seed for seeding purposes. Operators accustomed to drying corn or small grains may tend to overdry sunflower. About half as much water per bushel of sunflower needs to be removed per percentage point of moisture content as compared to corn or wheat. For example, drying corn from 25 percent to 15 percent moisture will remove 6.6 pounds of moisture per bushel. Drying sunflower from 20 percent to 10 percent removes only about three pounds of moisture per bushel.
Fire hazards exist in dryers used for sunflower.
Very fine hairs or fibers from the seed are rubbed loose during handling and are commonly found floating in the air around the dryer. These hairs or fibers ignite when drawn through the drying fan and open burner. A fire hazard is present unless these ignited particles burn themselves out before contacting the sunflower seed. The fire hazard is decreased if the fans are turned into the wind to draw clean air that does not contain fine hair or fibers, although this adjustment becomes a constant problem on days with frequently changing wind direction. A stationary dryer should be faced into the prevailing wind.