What type of oil must be used with all HFCs in HVAC/Refrigeration?

The correct answer is Polyolester oil. This type of oil is specifically designed for use with HFC (hydrofluorocarbon) refrigerants, which are commonly used in modern HVAC and refrigeration systems. Polyolester oils have excellent compatibility with HFCs and contribute to efficient system performance.

They are synthetic oils that provide good lubricity and thermal stability, making them ideal for use in systems operating at lower temperatures and pressures where HFCs are prevalent. Using the correct oil is critical because it affects the system's ability to lubricate, reduce friction, and maintain efficiency over time.

Other types of oils, such as mineral oil, alkebenzene, and polyethylene glycol, do not have the same level of compatibility with HFC refrigerants as polyolester oil. Mineral oils, for example, are typically used with HCFC and CFC refrigerants and may not provide the necessary lubrication and system protection when used with HFCs. This is why it is crucial to ensure the correct type of oil is utilized according to the refrigerant being employed.