Which of the following actions is not considered "major maintenance" under EPA regulations?

The action of replacing an oil filter is not classified as "major maintenance" under EPA regulations because it is typically considered a routine maintenance task rather than a significant repair or overhaul. Routine maintenance is usually preventive and aimed at keeping equipment running efficiently, while major maintenance involves substantial work on the system's components that affect its overall operation and safety.

In contrast, changing the compressor, overhauling the refrigerant system, and repairing leaking lines all involve significant repairs or replacements that impact the equipment's functionality and compliance with environmental regulations. These actions require more in-depth technical expertise, and they can potentially introduce new refrigerants or alter system performance, which is why they are categorized as major maintenance. Understanding this distinction is important for compliance with EPA regulations and for maintaining equipment performance efficiently.