Place short ribs in the crock of a slow cooker; season with salt and pepper.
Combine water, preserves, chili sauce, soy sauce, Worcestershire sauce, rice wine vinegar, honey, onion soup mix, red pepper flakes, onion powder, garlic powder, cinnamon, and ginger in a jar with a tight-fitting lid. Seal jar and shake until ingredients are well mixed; pour over the ribs, assuring all ribs are covered in sauce.
Cook on Low until the meat is fork-tender, 6 to 9 hours (or on High for 3 to 6 hours).
Any type of citrus preserve can be used, but if you can find the loquat preserves at your local Asian grocer, use it!