Which component protects compressor functionality by monitoring pressure levels in HVAC systems?

The low pressure limit control is vital for protecting the functionality of the compressor within HVAC systems. It monitors the pressure levels in the system and can shut down the compressor if the refrigerant pressure falls below a specified threshold. This is crucial because low pressure can indicate issues such as refrigerant leaks or insufficient refrigerant charge, both of which can lead to compressor failure. By providing this level of monitoring and protection, the low pressure limit control ensures that the compressor operates under safe conditions, thereby prolonging its lifespan and maintaining system efficiency.

In contrast to this, a bimetallic strip is typically used in thermostats and not specifically designed to monitor compressor pressures. The expansion valve regulates the flow of refrigerant but does not have a protective function regarding pressure levels. Similarly, the fan control switch manages the operation of the fan rather than monitoring or controlling compressor functions. Thus, the low pressure limit control is the most relevant component for ensuring the safe operation of the compressor in an HVAC system.