Chain problems:
CHAIN PROBLEMS: Be aware that chains can stretch and, this will change the effective center to center distance between links , also affecting the links per foot count. Look for links that are not totally closed .Squeeze them shut if possible. Where there are smaller chains (50- 60 links per foot or more) be particularly aware of chain links getting caught on each other , and knotting up. If this is not noticed before the knotted area of the chain gets inside the movement enclosure , it may not be discovered and you will have another unexplained problem