Crockpot Beef Stew

1 Packet McCormicks beef stew mix
1 Chuck roast, cut into bite-size pieces
2 1/2 Pounds potatoes, peeled & cut into bite-size pieces
1 Large onion, sliced & separated into rings
3 Carrots, cut into bite-size pieces
3 Celery stalks, chopped
1 (12 oz) Package frozen peas
5 Tablespoons flour
1 Tablespoon oil

Place cut roast in freezer bag with flour and shake to. Brown meat in oil in skillet then place in crockpot. Add potatoes, onion, celery and carrots to crockpot. Take packet of beef stew mix and thoroughly combine with 3 cups of water. Pour over ingredients in crockpot and cook on HIGH for 4 to 6 hours or LOW for 6 to 8 hours. Add peas about one hour before end of cooking time.