What is the function of a DPDT switch in an HVAC system?

A DPDT (Double Pole Double Throw) switch serves a crucial role in an HVAC system by reversing the direction of current flow. This action allows the switch to control the operation of certain components, such as motors in heat pumps and reversing systems. When the switch is activated, it changes the connections, effectively reversing the direction in which the motor runs. This capability is essential in applications where a heating and cooling function is required to be alternated without changing the physical wiring of the system. It provides a simple and effective method for controlling the operation of equipment that must run in both directions, ensuring versatile and efficient system functionality.