A different answer to the same problem
When the industry moved from CFCs and HCFCs to chlorine-free HFC refrigerants such as R-410A, R-407C, R-134a and R-404A, mineral oil stopped working. Mineral oil does not dissolve in HFCs, so it does not return to the compressor. The industry needed a polar synthetic oil that would mix with the new refrigerants, and two chemistries won: polyolester (POE) and polyvinyl ether (PVE).
POE became the general-purpose choice for commercial and industrial refrigeration, and it is the backbone of our RF POE range. PVE took a different route. Developed in Japan, it was adopted by many air-conditioning compressor and equipment makers, particularly for rotary, scroll and inverter-driven compressors in split, multi-split and VRF/VRV systems. Today, a large share of the ducted, cassette and VRF air-conditioning installed in South African offices, hotels, hospitals, shopping centres and homes leaves the factory charged with PVE.
What is PVE?
Polyvinyl ether is a synthetic polymer with ether (C–O–C) linkages along its chain. Like POE, it is polar, which makes it miscible with HFC refrigerants and lets it travel round the system and return to the compressor. The key difference is chemical: an ether bond is not an ester bond.
POE is made by reacting an acid with an alcohol, and water can run that reaction backwards (hydrolysis), turning the oil into organic acids. Ether linkages do not react with water in this way. PVE still absorbs moisture, and it must still be kept dry, but moisture does not break the oil down into acids. This is the property that made PVE attractive for air-conditioning, where systems are often installed on site with long field pipe runs and the risk of moisture getting in is higher.
PVE compared with POE
| Property | PVE (polyvinyl ether) | POE (polyolester) |
|---|---|---|
| Miscibility with HFCs | Good across HFCs including R-410A, R-407C, R-134a and R-404A | Good across HFCs; the standard choice for most refrigeration |
| Reaction with water | Does not hydrolyse into acids | Can hydrolyse into organic acids if moisture is present, especially when hot |
| Moisture absorption | Hygroscopic; must be kept sealed | Hygroscopic; must be kept sealed |
| Deposits and capillary blockage | Strong resistance; good solubility for process fluids from manufacture | Good when kept dry; acids and soaps can form deposits if hydrolysis occurs |
| Electrical insulation | High, suited to hermetic motors | High when dry |
| Typical applications | Rotary, scroll and inverter compressors in split, multi-split and VRF/VRV air-conditioning; some commercial refrigeration | Commercial and industrial refrigeration, chillers, screw compressors, CO2 (subcritical) and HFO systems |
Neither chemistry is "better" in every case. The right oil is the one the compressor manufacturer has approved for that compressor and refrigerant. What PVE offers is extra protection against moisture-driven chemical breakdown, which is why so many air-conditioning OEMs specify it.
Service rules every technician should know
- Check the nameplate or service manual. If the compressor or outdoor unit specifies PVE, top up and recharge with PVE of the specified viscosity grade.
- Don't swap to POE on a PVE system without OEM approval. It can affect oil return, compressor reliability and, on newer equipment, the warranty. PVE tolerates small amounts of other oils, but it is not an invitation to mix freely.
- Match the viscosity grade. PVE oils are commonly supplied around ISO VG 32, 50 and 68. Smaller rotary and scroll compressors tend to use the lighter grades and larger scroll and VRF compressors the heavier ones, but the OEM figure is what counts.
- Keep it dry anyway. PVE does not hydrolyse, but water in a system still causes freezing at expansion devices, corrosion and poor evacuation. Use sealed containers, charge with a closed pump, evacuate to 500 microns or better, and fit a correctly sized filter-drier.
- Never return oil to the container and never reuse oil drained from a system.
Why PVE matters for South Africa
VRF/VRV and inverter air-conditioning has grown quickly across South Africa and the region. Every one of those systems will eventually need oil: during installation top-ups, compressor replacements, leak repairs and system clean-ups after a burnout. Until now, contractors have mostly had to source PVE through OEM parts channels, often in small packs, at OEM prices and with variable availability.
Our customers have been asking us for a locally stocked, technically supported alternative. We have listened.
Introducing AA Lubricants RF-PVE: launching February 2027
AA Lubricants will introduce the RF-PVE Series of polyvinyl ether refrigeration oils to the South African market around February 2027. The range is being developed for HFC air-conditioning and refrigeration compressors that specify PVE, and will sit alongside our RF POE, RF PAG, RF PA, RF MO and RF VP ranges so that contractors can source all of their refrigeration lubricants from one local supplier.
What to expect from RF-PVE:
- Polyvinyl ether base oil that does not hydrolyse, with antioxidant and anti-wear additives
- Compatibility with HFC refrigerants including R-410A, R-407C, R-134a and R-404A
- Planned viscosity grades covering the most common PVE specifications in the field (ISO VG 32, 50 and 68)
- Stock in Johannesburg, with delivery or collection, and full technical data sheets and safety data sheets at launch
- Technical support from our team on grade selection, top-ups and system clean-ups
Final grades, pack sizes and specifications will be confirmed in our technical data sheets at launch.
Register your interest
If you service VRF/VRV, split or inverter air-conditioning and would like to be first in line for RF-PVE, or to receive samples and technical data as soon as they are available, email sales@aalubricants.co.za with your company name, the equipment brands you work on and the PVE grades you use most. In the meantime, our technical team is happy to advise on any POE or PVE lubrication question.
AA Lubricants: Always forward, never backwards.