Which of the following is NOT considered a major repair under EPA guidelines?

The correct answer is that refrigerant recovery is not classified as a major repair under EPA guidelines. Major repairs typically involve the replacement or significant repair of key components within an HVAC system, such as the evaporator, compressor, or auxiliary heat exchanger. These components are critical to the system's performance and efficiency, and their replacement often requires extensive work and may involve opening the refrigerant circuit.

Refrigerant recovery, on the other hand, is a process performed to retrieve refrigerants from the system for proper recycling or disposal. It is a maintenance or service task rather than a repair. This task is essential for compliance with environmental regulations but does not involve altering the structure or function of the HVAC system itself to the extent that a major component replacement would. Therefore, it does not meet the criteria of major repairs as defined by the EPA.