1Heat 1 1/2 cups water to boiling in 3-quart saucepan. Add potatoes and celery. Cover and heat to boiling; reduce heat. Simmer about 20 minutes or until potatoes are tender.
2Drain liquid into blender. Remove 3 cups cooked vegetables from saucepan; place in blender with liquid. Add 1/4 cup water. Cover and blend about 1 minute until smooth.
3Stir pureed vegetables back into saucepan. Stir in remaining ingredients; heat over medium heat, stirring occasionally, until hot.