Request suggestions for my shower
4 years ago we renovated our bathroom.
For our shower we got (pictured):
GROHE 35601000 Rapido Smartbox Universal Rough-In Box, Starlight Chrome
GROHTHERM® SMARTCONTROL SINGLE FUNCTION 2-HANDLE THERMOSTATIC VALVE Trim
Everything works well except from the start there’s been a problem with the knob for the shower. For context, turn counter clockwise to turn bathtub on, clockwise to turn shower on. There’s a “neutral” position that’s supposed to be at 12:00 (presumably) but for reasons I’m getting into, that neutral position moves.
So what happens is sometimes when we’re turning it (either direction), you hear a clicking sound and the neutral position moves. This has happened almost since the start, but lately it’s gotten really bad. As you can see in the pics, the cap has fallen off, so I took a pic of the inside of the knob. It looks like some kind of blue thing broke?
Right now I’m getting worried it’s going to get to the point that we can’t turn the shower on (or even worse, off). Does anyone know what this entails? Is the broken blue thing the problem? If so can I easily replace that? Or is this going to require a full plumber? Any help is appreciated.