What is the role of the float switch in an HVAC system?

The float switch in an HVAC system serves as a crucial safety device designed to monitor water levels, particularly in equipment like condensate drain pans or sumps. Its primary function is to shut off the HVAC system when water levels reach a certain height, preventing overflow and potential water damage. This is critical because excessive water accumulation can lead to operational failures, mold growth, or even property damage. By stopping the system, the float switch helps to protect both the equipment and the surrounding environment from the adverse effects of water accumulation.

Other functions listed in the choices focus on different aspects of HVAC operation, such as regulating compressor speed or controlling airflow, but these tasks involve separate components and systems, not the float switch.