These are fully synthetic refrigeration oils based on polyol esters (POE).
Intended for use with chlorine-free refrigerants, especially fluorinated ones like HFCs / FCs (e.g. R134a, R404A, R410A, R407C), and also suitable for HFOs and HFO/HFC blends.
Also usable with hydrocarbon refrigerants (propane, propylene, isobutane etc.), with suitable precautions.
Hygroscopic nature: Because esters absorb moisture from air, exposure to ambient air (humidity) must be minimized. Once container opened, use quickly.
Oil return: Need to ensure that system design allows the oil to return properly (pipe sizing, oil separators etc.), especially in open or semi-hermetic compressors. Some viscosity grades may be more challenging under low temperature or high load.
Higher cost than mineral oils: Synthetic esters are generally more expensive; but performance benefits can offset the cost in many applications.
Compatibility checks: While SE/SEZ oils are compatible with many refrigerants and materials, always check with manufacturer if retrofitting or replacing another oil type (e.g. mineral or alkylbenzene).
