What type of refrigeration oil should I use for my screw compressor?

Screw compressors typically require POE (Polyol Ester) oils for HFC refrigerants like R134a and R407C, or mineral oils for HCFC systems like R22. The viscosity grade (usually ISO VG 32-68) depends on the compressor manufacturer's specifications. Brands like Bitzer recommend BSE series POE oils, while FUSHENG systems often use mineral oil formulations.

What is the difference between POE and mineral refrigeration oil?

POE (Polyol Ester) oils are synthetic lubricants designed for HFC refrigerants (R134a, R404A, R407C, R410A) and are hygroscopic, requiring careful moisture control. Mineral oils (MO) are petroleum-based, used with CFC and HCFC refrigerants (R22, R502), and are less expensive but incompatible with modern HFC systems. POE oils offer better thermal stability and miscibility with newer refrigerants.

How do I select the right refrigeration oil for a centrifugal chiller?

For centrifugal chillers, select oil based on the OEM specification (e.g., Trane OIL00037, York PureOil S), the refrigerant type (R123 low-pressure or R134a medium-pressure), and the required viscosity grade. Most modern centrifugal chillers use POE oils with ISO VG 32-68. Always verify compatibility with the chiller manufacturer's technical bulletin and ensure the oil meets the required pour point for your operating conditions.