Delta & Single Handle Shower Faucet  "bath handles keep turning" Questions

...bath water my shower faucet is continuously running water. It won't stop. Pls suggest what could be the issue and best way to go about fixing it. It depends on what type of fixture you have. ...

turning it anti-clockwise it would not budge. Soak the unit in very hot water 50/50 with white vinegar for 2or 3 hours to loosen the lime in the threads and try it again. Keep the water hot no boiling