What is the purpose of a low pressure limit control?

The purpose of a low pressure limit control is to safeguard the compressor by preventing it from operating under dangerously low suction pressure conditions. When the pressure in the suction line drops below a certain threshold, the low pressure limit control will initiate a shutdown of the compressor. This is crucial because low suction pressure can lead to lower system efficiency, potential compressor damage, and even complete system failure. Protecting the compressor in this way helps to maintain the overall health and longevity of the heat pump system, ensuring reliable performance without risking costly repairs or replacements.

The other options focus on different aspects of the HVAC system. Regulating indoor temperature is more relevant to the thermostat's function, ensuring proper airflow pertains to duct design and blower operation, and maintaining refrigerant levels involves the management of the refrigerant circuit rather than being directly influenced by pressure control mechanisms.