How long should you pull a vacuum on noal change out of a compressor or condensor?

When changing out a compressor or condenser, you should pull a vacuum for at least 30 minutes to an hour, depending on the system's size and the amount of moisture present. The goal is to achieve a vacuum level of 500 microns or lower to effectively remove moisture and air. Using a vacuum gauge can help ensure that the system is adequately evacuated. Always follow manufacturer guidelines for specific requirements.