Shower Valve Handle Keeps Spinning Around.
I have a Dual Exposed Thermostatic Shower valve. It does not leak. The temperature is fine. The on/off lever handle however used to hit a stop point at off, and now does not - it goes around forever in circles (turning the water flow on and off as it goes around). It's fine for now (working OK, I drew a marker pen line to indicate when to stop turning to shut the water off), but it will need fixing. Is this a spare part I can get, or do I need to replace the entire valve?