ESCO Air Conditioning Practice Exam 2026 – The All-in-One Guide to Exam Success!

When the service technician finds the unit completely out of refrigerant, using a trace amount of refrigerant along with a compressible gas to pressurize the system is the correct choice. A compressible gas, such as nitrogen, is often used in this situation for leak checks and pressurizing the system to detect leaks effectively. It helps in isolating the system from outside air and moisture, making it easier to identify leaks and ensuring the system functions properly once it is recharged with the appropriate refrigerant. Therefore, using a compressible gas is essential for troubleshooting and maintaining the system's integrity.

Options B, C, and D are incorrect in this context:

- Option B, inert gas, may not be as effective as a compressible gas in pressurizing the system and detecting leaks.

- Option C, oxygen, should be avoided since introducing oxygen into the system can be dangerous and lead to the risk of fire or explosion.

- Option D, vacuum, is used for evacuating the system of air and moisture before charging it with refrigerant, but it is not suitable for pressurizing the system in this situation.