Place potatoes and carrots in slow cooker. Season with salt.
Combine egg, shredded wheat, chili sauce, onion, salt, marjoram, and pepper. Add ground beef. Mix well. Shape into loaf, slightly smaller in diameter than the cooker. Place on top of vegetables, not touching sides of cooker.
Cover. Cook on Low 9–10 hours.
Substitute ½cup bread crumbs or dry oatmeal for crushed shredded wheat biscuit.