An ideal oil is best at handling high temperatures and high pressures.

• A. It depends on the refrigerant
• B. True
• C. False
• D. Always the best option for all systems

Answer: (C)

The key idea is that oil performance isn’t universal. No single oil is best for every system under high temperature and high pressure. Oils are formulated to match specific refrigerants and operating conditions, balancing factors like thermal stability, viscosity at operating temperatures, oxidative resistance, lubricity, and compatibility with seals and the refrigerant. An oil that handles high temperatures well may not be ideal for a particular refrigerant or may have drawbacks at high pressures or at low temperatures, and vice versa. Because the best choice depends on the refrigerant and the system design, the statement that an ideal oil is best at handling both high temperatures and high pressures is not accurate.