Cook bacon until crisp. Add celery and onion to bacon drippings, setting bacon aside. Cook celery and onion until transparent. Stir flour into celery and onion and cook on low heat to remove raw taste from flour. Stir in water and vinegar cooking until thich and bubbly. Stir in sugar, salt and pepper. Pour over potatoes and add bacon to potatoes and toss lightly in a 3-quart casserole dish. Cover and bake at 350 degrees for 30 minutes.