Bitzer BSE85K POE Refrigeration Oil ISO VG85 for R744 CO2 Systems

How to Buy BSE85K: Terms, Packing and Documents

BITZER BSE85K is supplied on published terms: the pack sizes, the price terms, the payment terms and the documents are the same for every buyer, and they can be quoted without a site visit. The minimum order is deliberately left open, because it is judged case by case: the grade, the quantity, the pack size, the shipping terms and the container load all move it, so a single can and a full container load are both workable and neither is treated as the normal case. Send us the quantity, the destination port and whether your own brand goes on the container, and those three turn the table below into a firm quotation. Documents and lead time work the same way on every order: the technical data sheet and safety data sheet come with the quotation, and the certificate of analysis for the delivered batch comes with the shipment.

Full sourcing, OEM and private-label options are set out on our synthetic refrigeration oil sourcing page.

Is BSE85K the Right Grade for Your System?

What Else Can We Handle for Your Project?

A lubricant order is rarely only a lubricant order. The buyer is usually solving a grade question, an import documentation question, a freight question and a packaging question at the same time — often across more than one product family. Those are the parts of the job we take on, and they are handled by the same team that quotes the oil rather than passed to a third party.

None of this runs through a separate service department. The same technical contact stays with an account from the first grade question through to repeat orders, which is why a reorder does not start the conversation over again.

How to Order BSE85K

The system type comes before pricing, because BSE85K is the standard charge for one CO₂ duty and the alternative charge for another, and the grade cannot be confirmed until that is settled. The sequence is the same whether you are buying one can or a full container:

1. Send us the compressor or unit model, the refrigerant, the system type (transcritical or subcritical booster) and the quantity you need.
2. We confirm the oil against the BITZER data for R744 — including which of BSE60K, BSE85K and BSG68K your unit is charged with — and check whether a POE at this viscosity class is the right grade for the application.
3. We quote against your destination port on any Incoterms 2020 term (EXW, FOB, CFR, CIF, DDP and every other rule), with the pack size and the lead time for that quantity.
4. The technical data sheet and safety data sheet come with the quotation, and a certificate of analysis for the delivered batch comes with the shipment.

If you already know the grade and only need a price, send the quantity and the destination port and we will quote directly.

Technical Data — BITZER BSE85K

BITZER designates this grade by its basic viscosity at 40 °C rather than by an ISO VG class number, and 80 cSt does not reach an ISO VG grade in any case: it lies between the ISO VG 68 band of 61.2–74.8 cSt and the ISO VG 100 band of 90–110 cSt, both defined by DIN ISO 3448. Where this grade is labelled “ISO VG 85”, that number is not an ISO 3448 grade — standardise on the measured 40 °C value instead. The density can be linearly interpolated between the specified values. The water content and acid number figures are the used-oil warning limits BITZER publishes; the new-oil values come from the batch certificate of analysis, which is the document to ask for. A technical data sheet, a safety data sheet and a batch certificate of analysis are available for any grade we quote.

Approved Refrigerant and System Ranges for BSE85K

BITZER publishes the R744 oil charge by system type rather than by a refrigerant temperature matrix, and separately lists an application range on the HFC and HFO side. The two are reproduced below as they are published, because the same grade is documented for different duties in each.

Reading the table: the first four rows are the CO₂ story and they are the reason this grade exists. The fifth row is the only HFC / HFO entry BITZER publishes for BSE85K, and it is narrower than most buyers expect — it is a special-application charge at elevated evaporating or condensing temperatures, not a general HFC service oil. The last row is the boundary: above 40 bar suction or 120 bar high pressure the specified oil changes from a polyol ester to the PAG BSG68K. The specific compressor limits still come from the unit’s operating instructions or from BITZER’s own selection software.

Where Does BSE85K Sit in the BITZER CO₂ and POE Range?

BSE85K is one of three oils BITZER publishes for R744, and the choice between them is made on system type and pressure rather than on brand preference. In the wider refrigeration oil range there are heavier polyol esters and complex esters as well.

The viscosity is the basic viscosity at 40 °C as BITZER publishes it. Note that the three CO₂ grades are not simply a viscosity ladder: BSE60K and BSE85K are polyol esters and BSG68K is a polyalkylene glycol, and the switch between them is triggered by pressure limits rather than by the duty. A grade is only an equivalent if both the chemistry and the viscosity class match, so compare the whole row and not just the cSt figure.

Which Oils Can Replace BSE85K?

If your compressor is already in service, you probably hold a data sheet for a different brand at a comparable viscosity. These are the oils stocked on this site whose published 40 °C viscosity is close enough to be worth checking, with the Qishanr equivalent at this class:

A cross-reference here matches the viscosity, which is the smaller half of the selection on a CO₂ circuit. BSE85K is a polyol ester specified for R744 transcritical and booster duty, and the oils above are documented for other refrigerants — a 68 cSt mineral or a 104 cSt screw oil is not an equivalent just because the number is close. The cSt figures in this table come from each product’s own published data on this site, not from BITZER’s sheets. Send us the compressor model, the refrigerant and the current oil and we will confirm the correct grade rather than leave the match to a table.

What BSE85K Is, and Why CO₂ Needs Its Own Grade

BSE85K is a polyol ester at 80 cSt, and the reason BITZER keeps a separate grade for carbon dioxide is that R744 does not behave like the refrigerants the lighter esters were developed for. It is highly soluble in oil, which reduces the viscosity of the film that is actually protecting the bearings, and it raises the pressures in the circuit well above what an HFC system sees. The published operating guidance for R744 reflects both: a recommended suction gas superheat of 20 K to keep the refrigerant concentration in the oil down, a minimum discharge gas temperature of the condensing temperature plus 40 K, and a ceiling of 140 °C measured on the discharge line. The heavier 80 cSt grade is what gives the film its margin under those conditions.

The chemistry is the other half. BSE85K is a polyol ester, which means it is hygroscopic and has to be handled dry — and on a CO₂ circuit moisture is not only a lubricant problem, it is a system problem, because water in the circuit reacts with carbon dioxide to form acid. BITZER states that this oil significantly exceeds the DIN 51503-1 requirements for refrigeration compressor oils on water content and total acid number, which is the reason to keep the containers sealed and to use clean, dry transfer equipment.

Transcritical or Subcritical — Why the Distinction Comes First

BITZER’s own documentation splits BSE85K by system type, and the split is not cosmetic. On a transcritical CO₂ circuit — one that runs above the critical point, so the high side is a supercritical fluid rather than a condensing liquid — BSE85K is the standard oil charge. On a subcritical circuit, such as a cascade or a booster system, the standard charge is the lighter BSE60K, and BSE85K is the alternative. AT-744-2 is more specific still for booster units with POE oils: on the 2NSL–4NSL and 2MME–6PME compressors, BSE85K is the oil to use.

That is why this page asks for the system type before it quotes. The same 80 cSt drum serves both duties, but a buyer who orders it for a subcritical cascade because “heavier must be safer” has moved away from the published standard charge, and the difference shows up in oil return and in how much refrigerant the oil holds. The selection is made against the application, not against the number on the drum.

Frequently Asked Questions

Q: What is BITZER BSE85K, and what is it used for?

A: BITZER BSE85K is a polyol ester (POE) refrigeration oil with a basic viscosity of 80 cSt at 40 °C, and it is one of the three oils BITZER publishes for R744 (CO₂). It is the standard oil charge for transcritical CO₂ applications and the alternative oil charge for subcritical booster applications, and the compressor type designation carries a “K” — 4FTE-30K, for example. On the HFC and HFO side it is listed only as an oil charge for special applications with R1234ze(E), so it is not a general-purpose HFC service oil.

Q: Is BSE85K an ISO VG 85 oil?

A: No — ISO VG 85 is not a grade. DIN ISO 3448 defines the viscosity classes in fixed steps, and there is no VG 85 among them. BSE85K measures 80 cSt at 40 °C, which falls between the ISO VG 68 band (61.2–74.8 cSt) and the ISO VG 100 band (90–110 cSt), so no ISO VG number applies to it at all. BITZER designates the grade by its measured basic viscosity rather than by a VG class, which is why this page quotes the cSt figure throughout. If a supplier lists an “ISO VG 85” oil, compare the 40 °C viscosity on the certificate rather than the label.

Q: What is the difference between BSE60K, BSE85K and BSG68K for CO₂?

A: They are the three oils BITZER documents for R744, and the choice is made on system type and pressure. BSE60K (the same oil as BSE55, 55 cSt) is the standard charge for subcritical applications such as cascade systems. BSE85K (80 cSt) is the standard charge for transcritical applications and the alternative for subcritical boosters. BSG68K (68 cSt) is a polyalkylene glycol rather than a polyol ester, and it is a precondition for applications with suction pressure above 40 bar or high pressure above 120 bar, such as heat pumps. Note that the three are not a simple viscosity ladder: the switch to BSG68K is triggered by pressure limits and it changes the oil chemistry, not only the thickness.

Q: Can BSE85K be used in R134a, R404A, R407C or R507A systems?

A: BITZER’s published application range for BSE85K on the HFC and HFO side lists only R1234ze(E), and only as an oil charge for special applications at evaporating temperatures above 15 °C or condensing temperatures above 70 °C. For ordinary HFC service such as R134a, R404A or R407C, the published grades are the lighter polyol esters — BSE32 or BSE55 — and using a heavier oil is a different selection rather than a safer one. Send us the compressor model and the refrigerant and we will confirm which grade applies rather than working from the label.

Q: How do I know whether my system is transcritical or subcritical?

A: Transcritical means the high side of the circuit runs above the critical point of CO₂, so the gas cooler never condenses the refrigerant into a liquid; subcritical means it does condense, as in a cascade or a booster system. In practice the compressor model and the unit documentation settle it, and it matters because it decides whether BSE85K is the standard charge or the alternative one. Send us the compressor model and we will work it out before quoting — getting it wrong is one of the more expensive ways to mis-order a drum of oil.

Q: Is there a minimum order for BSE85K, and what pack sizes are available?

A: BSE85K ships in 1 L, 5 L, 10 L, 20 L and 208 L packs. There is no fixed minimum order — it is confirmed per order, because it depends on the pack size, the quantity and the destination, and a single can and a full container load are both workable. In practice the quantity is rarely the only variable: the shipping terms and the container load move the figure as well, so we quote against the order rather than against a price list. Custom pack formats and private-label artwork are available as a quotation item, so if your own label has to go on the container, say so when you enquire and it is quoted as part of the project rather than added afterwards.

Q: Does the oil in the system need to be flushed before changing to BSE85K?

A: It depends on what is in the system now. Within the same viscosity group, BITZER permits mixing polyol esters with the original oil provided appropriate experience is available for the application, and the precondition for any alternative oil is a guaranteed moisture content below 50 ppm. What the document does not support is mixing oil types: a polyol ester and a mineral oil, or a polyol ester and a polyalkylene glycol such as BSG68K, are not interchangeable without a proper changeover. The seal material matters here as well — for R744 with POE and PAG oils the recommended elastomers are hydrogenated nitrile rubber with a nitrile content above 36%, EPDM and fluorinated rubber. Send us the oil you are running and the compressor model and we will confirm whether a flush is needed and what the changeover sequence is.

Q: What documents come with an order?

A: The technical data sheet and the safety data sheet come with the quotation, so the grade can be checked before the order is placed. The certificate of analysis for the delivered batch comes with the shipment, so the actual figures for the oil in the container can be filed with the service record — which matters most on a CO₂ circuit, where the new-oil water content and acid number are what you are guarding. Export documentation is prepared as standard for overseas orders: CE, certificate of origin, MSDS and transport identification report. Third-party testing by SGS or another laboratory is arranged on request, and the printed documents are supplied in the language the receiving authority requires.

Q: What price and payment terms apply?

A: Price is quoted against your destination port on any Incoterms 2020 term — EXW, FOB, CFR, CIF, DDP and every other rule — so the delivered figure is known before the order is placed rather than assembled afterwards from separate freight quotes. Payment is on any commonly used method, including T/T, L/C and PayPal, confirmed with the order. Long-term partners get pricing that reflects a stable manufacturing base rather than a trading margin. Send the quantity and the destination port and we will quote directly.

Key Takeaways

• BITZER BSE85K is a polyol ester (POE) refrigeration oil with a basic viscosity of 80 cSt at 40 °C, designated for R744 (CO₂) systems on BITZER reciprocating compressors marked “K”.
• It is the standard oil charge for transcritical CO₂ applications and the alternative oil charge for subcritical booster applications.
• 80 cSt is not an ISO VG grade: it falls between the ISO VG 68 band (61.2–74.8 cSt) and the ISO VG 100 band (90–110 cSt), and DIN ISO 3448 has no VG 85.
• Above 40 bar suction pressure or 120 bar high pressure BITZER specifies the PAG BSG68K instead — the boundary is pressure, not duty.
• The used-oil water limit is 150 mg H₂O/kg under group KB for R744 service and 200 mg H₂O/kg under group KD for HFC and HFO service; BITZER gives a different group for each.
• R1234ze(E) at evaporating temperatures above 15 °C or condensing above 70 °C is the only HFC / HFO entry BITZER publishes for this grade, as a special-application charge.
• Available in 1 L, 5 L, 10 L, 20 L and 208 L packs, as the original BITZER oil or as our equivalent 80 cSt POE made to order in Foshan, China.
• Any Incoterms 2020 term (EXW, FOB, CFR, CIF, DDP and others), any commonly used payment method (T/T, L/C, PayPal and others).
• Minimum order is confirmed per order — a single can and a full container load are both workable.

Standards and Sources Behind the Data on This Page

Every figure on this page is taken from a published document, and each one is listed here so it can be checked. Where two documents give the same value, both are cited.

Standards are cited to the publisher’s official catalogue entry rather than to a summary, and the documents listed here were checked as reachable when this page was last reviewed. Technical data sheets for the original BITZER grades and for our own equivalents are available on request and are supplied with every quotation.