Make sure you don't' commit the following two big sins of sunflower drying and storage.
1) Not using enough air. Aeration fans should deliver 1/10 to 1 cubic foot per minute of air. Aeration is essential, especially in larger bins. If aeration is not available, sunflower should be rotated between bins to prevent hot spots from developing.
2) Turning up dryer temperature too high. Ambient air can be used to cool and dry sunflower. If heated air is used, generally a 10 degree F increase in temperature over ambient is sufficient to increase the drying rate. Sunflowers dry more rapidly than corn or soybeans, and must be monitored to avoid over drying.
3) Ignoring fire dangers. Fine fibers from sunflower seeds pose a constant fire hazard, especially when conditions are dry. Keep the combine and grain dryer free of chaff and dust (consider having a portable leaf blower on hand for this). Keep a small pressure sprayer or container filled with water on hand in the combine in case of fire. If the threat of extreme dry conditions and combine fires persists, try nighttime harvesting, when humidity levels are higher.
Source: NDSU and SDSU Extension services