Fry bacon in a skillet until crispy. Set bacon aside, and retain the bacon fat. Transfer retained bacon drippings to a stock pot. Over medium heat, cook the onion in bacon fat until translucent. Add chicken broth, water, potatoes, salt, dill weed, white pepper, carrot, and celery. After 10 minutes, cover, reduce heat, and cook for 2 hours, stirring frequently. In a medium bowl, mix flour, half and half, and evaporated milk. Add this mixture to the soup and cook for another 20 minutes. Crumble retained bacon and use as a garnish.