1In 5-quart Dutch oven, cover potatoes with water. Heat to boiling; reduce heat to low. Cover; cook potatoes 20 to 25 minutes or until tender. Drain; cool 10 minutes.
2Peel potatoes; cut into 1/2-inch cubes. Place in large bowl.
3In small bowl, beat mayonnaise, mustards, dill weed, salt and pepper with whisk. Toss potatoes with mayonnaise mixture. Stir in celery and onion until well blended.
4Cover; refrigerate about 1 hour to blend flavors. Serve cold. Cover and refrigerate any remaining salad.