When should a technician use a vacuum pump during MVAC service?

A vacuum pump is used during MVAC service primarily after repairs and before recharging the system with refrigerant. This step is crucial because it helps to remove moisture, air, and any contaminants that may have entered the system due to previous repairs or openings. Moisture in an air conditioning system can lead to the formation of acids and sludge, which can damage components and degrade system performance. By using a vacuum pump, technicians create a vacuum that is effective in pulling out any trapped air and moisture, ensuring a clean and efficient environment for the refrigerant once it is reintroduced.

Using a vacuum pump before any service is performed does not effectively address any moisture or contaminants because those issues may not be present until the system has been opened. Charging the system in the final stages without first vacuuming it out could lead to reintroducing moisture and air, which harms the efficiency and longevity of the system. Similarly, using a vacuum pump only after a leak has been detected does not prevent contamination and moisture from affecting the system throughout its operation, making proactive vacuuming after repairs the most effective practice for maintaining system integrity.