scalding

This shower valve, at its hottest setting, runs at least 10° less than the sink faucet that is right next to it. Is there some kind of internal adjustment to it? Perhaps to protect against scalding? Our kid is now a grownup and wants his showers hotter, and if I don't fix it I'm afraid he will...

Hi, everyone. This is my first post, so please forgive me if I'm not providing enough information, too much info, or not explaining things clearly. I can unclog drains and turn water lines on and off...that is where my plumbing experience ends. :) We live in the Twin Cities (MN) and our home...