How Long Should You Pull Vacuum on Your Car AC System?
The duration to pull vacuum on a car AC system depends on the type of pump used, the size of the AC system, and the level of contamination. Generally, it takes anywhere between 30 minutes to an hour to evacuate all the air and moisture from the system until the pressure reaches 29.92 Hg or -15 psi. However, it is recommended to leave the vacuum pump on for at least an hour to ensure a thorough evacuation of contaminants.