The "temperature adjust" knob on our Delta Monitor doesn't work while the water is running. Once you turn the water off and back on, the new temperature setting will take effect. Annoying, but we've lived with it a while. I'd like to fix it!
I'm not exactly sure which model we have, but I'm pretty sure it's a Delta Monitor since the trim piece says "Delta" at the top and "Monitor" at the bottom. (See attached photo)
My mom says they discussed this problem on "This Old House" and there was an easy fix, but she doesn't remember what the fix was. The water is pretty "hard" here. Maybe we just need to disassemble it and soak it in a 50/50 vinegar/water mix?
Have you seen this? Know how to fix it?
Thanks for any advice!