Rinse beans. In a large pot combine beans and 8 cups water. Bring to boiling; reduce heat. Simmer, uncovered, for 10 minutes. Remove from heat. Cover and let stand for 1 hour. Drain and rinse beans.
Coat the inside of a 4- to 6-quart slow cooker with cooking spray. Add beans, 4 cups water, and carrots to slow cooker. Cover and cook on low-heat setting for 6 hours.
Increase to high-heat setting. Add tomatoes, pasta, zucchini, beans, salt, and pepper. Cover and cook for 45 minutes more. Serve topped with cheese, if desired.