Canal TVi Automecânica, válvula termostato, sabe para o que serve?

<iframe width="560" height="315" src="https://www.youtube.com/embed/Jv7iciF4Hbk?si=QxMCUrJGztcL6WON" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>