I have a double drop jet pump on the well that supplies water to my home. There is a pressure regulator on top of the pump with a pressure gauge. What is the exact use of this pressure regulator? Is it a backpressure regulator for the jet? If so, what should the regulator pressure be set to? This is not a familiar system to me and the home was just purchased and I'd like to familiarize myself to it's workings.

Any help you can provide would be appreciated.

Thank you!