What is the purpose of a vacuum pump in an HVAC system?

The purpose of a vacuum pump in an HVAC system is primarily to remove air, moisture, and non-condensables. This process is crucial during the installation and servicing of refrigeration and air conditioning systems. Before charging the system with refrigerant, a vacuum pump is used to create a vacuum that eliminates any unwanted gases and moisture that could adversely affect system performance and longevity.

Moisture in the system can lead to the formation of ice or acids, which can cause corrosion and damage to components. Air and non-condensables can also hinder the refrigerant's ability to absorb and release heat, resulting in reduced efficiency and potential damage to the system. By ensuring that the system is free from these contaminants, the vacuum pump helps to guarantee optimal operation and efficiency.

The other options do not accurately represent the function of the vacuum pump. Increasing pressure within the system and circulating refrigerant are roles played by compressors rather than vacuum pumps. Likewise, maintaining a constant temperature is a function managed by the thermostat and the overall design of the HVAC system, rather than by the vacuum pump itself.