Drain juice from clams into a large skillet over the onions, celery, potatoes and carrots. Add water to cover, and cook over medium heat until tender.
Meanwhile, in a large saucepan, melt the butter over medium heat. Whisk in flour until smooth. Whisk in cream and keep stirring until it is thick and smooth. Stir in veggies and clam juice. Heat through, but do not boil.
Stir in clams just before serving. When clams are heated through, stir in vinegar, and season with salt and pepper.
Serves about 8