Flow Switch

A flow switch in a hot tub is a safety mechanism designed to prevent harm to the hot tub heater. 
It plays a pivotal role in keeping your hot tub running smoothly, ensuring that heated water is circulating through the system properly, and keeping your hot tub safe by preventing the heater from overheating.

Flow switches come in two types: paddle switches and pressure switches. 
Both perform the same task of sending a signal to the electrical controls that allow the heater to turn on when sufficient water is flowing through the spa’s piping system.

On either side of the hot tub, there is a sensor that reads the water pressure flowing through the system or a pressure switch located on your heater element which does the same. 
These sensors check the flow of water and prevent it from going dry.