Italian Beef Barley Soup

2 pounds cubed beef chuck roast
5 cups water
4 cubes beef bouillon, crumbled
1/2 onion, chopped
1 (8 ounce) can tomato sauce
3/4 cup uncooked pearl barley
Salt and pepper to taste

In a crockpot, combine beef, water, bouillon, onion, tomato sauce, barley, salt and pepper. Cover, and cook on LOW for 5 hours.