This page is for anyone looking for oil for an oil-flooded screw air compressor: which viscosity grade, which base oil, how to read the oil label and the manual of each compressor make, and the Lubrizol CPI line for each base oil. Send the machine model, running hours and discharge temperature; a Hop Tien engineer selects the oil within 24 working hours.
Most oil-flooded screw air compressors in Vietnam use ISO VG 46; VG 32 for small machines or where the compressor manufacturer specifies it; VG 68 for reciprocating compressors and hot-running machines. The base oil decides the drain interval and how the change is done: hydrotreated mineral oil (CPI-9370-46, oil life up to 4,000 hours per TDS) for machines running mineral oil under normal conditions; PAO (CPI-4601) where a longer interval is wanted or the discharge temperature is above the normal level in the machine manual (reference 8,000 hours per the CPI brochure at 82 °C discharge, to be confirmed by oil analysis); PAG/ester (CPI-1522-46) for machines factory-filled with an oil of the same base or in hot, humid compressor rooms; NSF H1 registered oil (CPI-4265-F, CPI-4600-F, CASSIDA FLUID CR) where the compressed air may touch the product. Before changing, read the oil label to know the base oil in the machine, check the actual running hours, varnish and the compressor manufacturer's warranty requirements; the engineer fixes the grade after seeing the machine and an oil sample.
| Base oil | When to choose it | Hop Tien line (per TDS) |
|---|---|---|
| Hydrotreated, isodewaxed mineral | Machine running mineral oil, dry compressor room, discharge temperature within the normal range in the machine manual; oil life up to 4,000 hours per TDS, confirmed by oil analysis | CPI-9370-46 (47.61 mm²/s at 40 °C, flash point 221 °C, pour point −45 °C) |
| PAO (synthetic hydrocarbon) | Longer interval wanted, discharge temperature above the normal level in the machine manual, less varnish; PAO is miscible with mineral oil per the PDS, so changing from mineral oil is straightforward (still drain the old oil fully and replace the filter and separator element). Reference oil life 8,000 hours per the CPI brochure at 82 °C discharge, to be confirmed by oil analysis | CPI-4601-32 · CPI-4601-46 · CPI-4601-68 · CPI-4601-100 · CPI-4601-150 (per the CPI PDS: acceptable for use where H2 products are permitted; not an NSF registration) |
| PAG + polyol ester | Machine factory-filled with the compressor manufacturer's PAG/ester oil, or a hot and humid compressor room; not miscible with mineral oil or PAO, a change of base requires draining and flushing | CPI-1522-46 (45.74 mm²/s at 40 °C, flash point 264 °C, pour point −52 °C) |
| NSF H1 registered (food and pharmaceutical plants) | Compressed air may touch the product, or an audit requires H1 oil for the compressor | CPI-4265-46F · CPI-4265-68F (PAO + ester) · CPI-4600-32F to 150F (PAO) · CASSIDA FLUID CR 100 (NSF H1 registered, ISO 21469) |
| Viscosity grade | Typical machines | Notes |
|---|---|---|
| ISO VG 32 | Small screw compressors, machines in cool locations; some compressor manufacturers specify VG 32 for synthetic oil | Use only when the machine manual states VG 32; lowering the viscosity arbitrarily thins the oil film at the bearings |
| ISO VG 46 | Most 7.5–250 kW oil-flooded screw compressors in Vietnam | The common grade; choose CPI-9370-46, CPI-4601-46 or CPI-4265-46F by the base oil in the machine and the H1 requirement |
| ISO VG 68 | Reciprocating compressors, hot-running screw compressors, or where the compressor manufacturer specifies VG 68 | High discharge temperature and continuous load; CPI-4601-68 or CPI-4265-68F |
During the warranty period or a service contract, use an oil on the compressor manufacturer's list. After the warranty, the first thing to know is the base oil in the machine; this information is in three places on your own machine and is not inferred from the compressor make:
Hop Tien has changed the oil in screw compressors of these makes; the grade is chosen by the base oil in the machine, the discharge temperature, the compressor-room humidity and the H1 requirement, not by the compressor make.
Compressor makes are named so that readers can find the right documents for their own machine; Hop Tien does not represent these compressor manufacturers. Confirm the base oil from the oil label and the manual of that particular machine.
Details and the base-oil table of common air compressor oils: switching from another manufacturer's oil. Price by base oil, pack size and service: how to get a quotation.
Oil for oil-flooded screw air compressors: mostly ISO VG 46, hydrotreated mineral or PAO; VG 32 or 68 where the compressor manufacturer specifies it. Food plants choose NSF H1 registered oil. Read the oil label and the machine manual first to know the base oil in the machine, then choose the CPI line of the same base.
When the discharge temperature is above the normal level in the machine manual, consider a synthetic oil: PAO such as CPI-4601-46 (flash point 279 °C per TDS) if the machine is running mineral oil or PAO; PAG/ester such as CPI-1522-46 if the machine is running an oil of the same base or the compressor room is hot and humid. There is no fixed °C threshold; the engineer decides after seeing the machine and an oil sample, and the separator and filter are replaced at the change.
By running hours and oil analysis results, not on a fixed schedule. Reference figures: mineral CPI-9370-46 up to 4,000 hours per TDS; PAO CPI-4601 8,000 hours per the CPI brochure at 82 °C discharge; a discharge temperature above normal and high humidity shorten the interval, so it must be confirmed by oil analysis on each machine. Sample at 500 hours after the change and periodically thereafter.
CPI's PAO (CPI-4601) is miscible with mineral oil per the PDS, so changing from mineral to PAO only requires draining the old oil fully and replacing the filter and separator element. PAG/ester oil does not mix with mineral oil or PAO: a change of base requires a complete drain and flush.
When the compressed air may come into incidental contact with the product or packaging, or an audit requires it, use an NSF H1 registered oil such as CPI-4265-46F or CPI-4600-46F; if the compressed air does not touch the product, a standard oil can still be used, but this should be recorded in the lubrication chart.
Machine model and power, the oil in use (photo of the drum label), machine hours and oil hours, discharge temperature, current change interval and the problem you are facing. The engineer replies within 24 working hours with the TDS of the proposed grade.
Temperature, viscosity and registration data are given per the manufacturer's TDS published on each product page; the actual conditions of the machine decide the final choice. Compressor makes and trademarks named on this page belong to their respective manufacturers.
Each page has TDS data, registrations, pack sizes and a form to request documents.
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