Identify Shower Temperature Problem

What happens here

The video begins with the presenter showing a newly installed shower where the water, even at its hottest setting, is only warm. This indicates a potential miscalibration of the shower valve's anti-scald feature, which prevents the water from reaching a sufficiently hot temperature. The first step is to confirm this problem by running the shower at its maximum hot setting and observing the water temperature.

Goal: Confirm the shower is not reaching desired hot water temperature.