What is the purpose of a low pressure cut-out switch?

The purpose of a low pressure cut-out switch is to establish a minimum operating pressure in the evaporator. This device plays a critical role in protecting the system from operating under conditions that could lead to inefficient performance or damage to the system components.

When the pressure in the evaporator drops below a predefined threshold, the low pressure cut-out switch activates, shutting down the compressor. This action prevents the evaporator from operating at too low a pressure, which could result in inadequate refrigerant flow, potential freeze-ups, or excessive wear on the compressor. By maintaining a minimum pressure, the switch helps ensure optimal system performance and longevity.

In contrast, other options refer to different functionalities. For instance, high-pressure cut-out switches are responsible for preventing the condensing pressure from becoming excessively high, which is a different aspect of system safety. Detecting oil pressure is crucial for a compressor's lubrication system but not the main role of a low pressure cut-out switch. Similarly, cycling the evaporator blower relates to maintaining air flow rather than monitoring pressure levels. Therefore, the focus of the low pressure cut-out switch is primarily about establishing and maintaining safe operating pressures within the evaporator.