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.

Complete Analysis of Mcquay A Refrigerating Oil: Characteristics, Operation and Troubleshooting Guide

Por Qishanr Lubricants January 28th, 2026 vistas 28

I. Core Characteristics of Mcquay A

1. Key Technical Parameters

Viscosity: 32.5cSt at 40℃, 5.8cSt at 100℃, with a 121 viscosity index for stable performance across wide temperatures.
Temperature Adaptability: Pour point -46℃ (low-temperature start-up) and flash point 258℃ (high-temperature safety).
Stability: Acid value ＜0.05mgKOH/g, resisting oxidation and hydrolysis to reduce sludge and corrosion.

2. Core Functions

It integrates lubrication (reducing wear), sealing (preventing refrigerant leakage), cooling (dissipating heat), and capacity regulation (ensuring smooth load switching).

II. Operation & Maintenance Specifications

1. Oil Change Cycle

New units: Change oil after 2500 hours (3 months) and clean filters.
Normal operation: Change every 10000 hours (1 year); 6-8 months for harsh conditions.
Emergency: Replace immediately if oil turns black, has a burnt smell, or the unit malfunctions.

2. Centrifugal Compressor Oil Change Steps

Close 4 valves (supply, return, suction, balance) and drain old oil.
Replace 4 oil pump filters and remove impurities.
Inject new oil to the standard level.
Assemble and bleed air to avoid blockage.

3. Precautions

Keep POE oil sealed to avoid moisture; never mix with other oils; follow the manual for filling quantity to prevent liquid hammer or poor lubrication.

III. Common Troubleshooting

Oil Blockage: Replace oil, flush the circuit with 1.5x oil quantity, and optimize the return pipeline slope to ＞1/100.
Oil Leakage: Check the oil level switch for alarms; use high-temperature oil return mode for no-oil-level issues; replace shaft seals or use ejectors for leakage.
Oil Deterioration: Test oil index every 6 months and avoid long-term high-temperature operation.

IV. Selection & Replacement Tips

Only for R134A systems (R22 uses Mcquay C/D). Alternatives: Lanxess EVEREST32/RL32H (POE32), with thorough system cleaning before replacement. Buy OEM-certified products and store sealed.