Part 1: Sauté onion in some butter over medium-high heat until soft. Place onion in slow cooker, and stir in chicken broth, water, potatoes, salt, dill weed, garlic, and pepper. Cover and cook on low 6 to 7 hours. Cook the bacon separately, drain on paper towel, and refrigerate until ready to serve as topping. Part 2 (30 mins before serving): Test to make sure potatoes are done. If not done, turn on high for awhile to make sure potatoes are done. In a small bowl, whisk together the flour and heavy cream. Stir into the soup along with the evaporated milk and Velveeta Cheese. Cover, and cook another 30 minutes before serving.