Mineral refrigeration oil selection starts with the compressor and equipment lubricant specification, then checks refrigerant suitability, viscosity, materials and operating conditions. R22, R717, R290 or R600a may narrow the candidate oil family, but none of those refrigerant names is enough to approve a 3GS, 4GS or 5GS oil for a specific system.
For procurement, request the compressor model, current oil, required viscosity, refrigerant, evaporating and discharge conditions, service history and OEM document before releasing a purchase order. This prevents a common error: buying a chemically plausible oil that has the wrong viscosity or is not approved for the installed compressor.
The buyer is not choosing only between mineral oil and synthetic oil. The real decision includes base-oil family, viscosity, low-temperature behavior, refrigerant interaction, compressor design and the condition of oil already inside the circuit. A correct quote therefore needs more than a refrigerant number.
Naphthenic mineral refrigeration oils are used in many legacy and application-specific systems because they can provide useful low-temperature properties and refrigerant interaction. That statement is a category description, not a universal compatibility claim. The installed equipment documentation remains the controlling source.
| Refrigerant | Where mineral oil may appear | Main procurement risk | Evidence required before purchase |
|---|---|---|---|
| R22 | Legacy HCFC refrigeration and air-conditioning equipment | Assuming every R22 compressor uses the same grade; ignoring retrofit history | Compressor model, nameplate, OEM oil grade, current oil and retrofit record |
| R717 ammonia | Industrial ammonia systems where the compressor maker specifies an appropriate mineral oil | Ignoring oil carryover, operating temperature, materials or compressor-specific requirements | OEM manual, compressor type, viscosity requirement, oil separator arrangement and operating envelope |
| R290 propane | Selected hydrocarbon systems designed and approved for a mineral lubricant | Treating hydrocarbon miscibility as complete equipment approval; overlooking flammability controls | Equipment approval, charge and service procedure, compressor specification and lubricant grade |
| R600a isobutane | Selected small hermetic systems using an approved mineral lubricant | Using a generic refrigeration oil without checking compressor and factory-fill requirements | Compressor data sheet, original oil, approved viscosity and sealed-system service instructions |
The matrix is a screening tool, not an approval chart. It identifies which documents must be collected. It does not authorize substituting one oil for another or mixing oils in service.
GS designations are often used as commercial grade names, but procurement should compare the actual technical data rather than infer equivalence from the label alone. The following QISHANR values come from current first-party product records and should be confirmed against the quotation TDS or certificate required for the order.
| Reference grade | Kinematic viscosity at 40°C | Kinematic viscosity at 100°C | Pour point | Procurement interpretation |
|---|---|---|---|---|
| QISHANR 3GS | 30 cSt | 4.4 cSt | -40°C | Lower-viscosity candidate; close to an ISO VG32 purchasing conversation, subject to OEM limits |
| QISHANR 4GS | 55 cSt | 5.9 cSt | -36°C | Mid-viscosity candidate; do not substitute for 3GS or 5GS from grade name alone |
| QISHANR 5GS | 100 cSt | 8.4 cSt | -24°C | Higher-viscosity candidate; requires explicit compressor and temperature-range confirmation |
These values show why 3GS, 4GS and 5GS are not interchangeable. Moving from 30 cSt to 100 cSt changes flow resistance, oil return and bearing-film behavior. A higher viscosity is not automatically better protection, and a lower viscosity is not automatically better at low temperature.
For an operating R22 system, begin with the factory lubricant and compressor specification. Record whether the circuit is original, repaired or converted, because residual POE, alkylbenzene or another oil can change the service decision.
If the project is an R22-to-HFC conversion, this article is not the conversion procedure. Use the R22 retrofit oil conversion guide and the replacement refrigerant manufacturer's instructions, because residual mineral oil and POE conversion requirements are separate engineering questions.
R717 procurement needs compressor-specific review because industrial ammonia systems vary widely in compressor type, oil separation, temperature and service practice. The purchase specification should state whether the machine is reciprocating, screw or another design, plus the required viscosity and operating envelope.
Do not approve oil from the word “ammonia-compatible” alone. Ask for the applicable TDS, material compatibility information, oil-separator conditions and any OEM approval or cross-reference that the buyer requires. Where a warranty or regulated maintenance program applies, obtain written acceptance.
R290 and R600a are hydrocarbon refrigerants. A lubricant may be technically considered for a designed application, but that does not authorize refrigerant conversion or field servicing outside the equipment procedure. Flammability classification, charge limits, ventilation, ignition-source control and technician competence remain separate requirements.
For R290, avoid duplicating a general refrigerant overview; the useful procurement question is whether the named compressor and factory fill support the proposed mineral oil. For R600a, small hermetic equipment often requires strict adherence to the compressor or appliance specification. In both cases, confirm the exact grade and service method before opening the system.
Mineral oil, POE and PAG are different lubricant families. Mixing can change viscosity, miscibility, moisture behavior, additive balance and oil return. Even when two fluids appear physically blendable, the resulting mixture may no longer match either product's documented performance.
For a chemistry comparison, read POE oil vs mineral oil. For HFC systems, use the HFC refrigeration oil compatibility guide. A conversion should follow the compressor, refrigerant and equipment procedures rather than a generic flushing percentage.
| Pack size | Typical procurement use | Control point |
|---|---|---|
| 1 L | Samples, small service jobs or controlled evaluation | Confirm that the volume covers flushing, charging and unavoidable handling loss |
| 4 L / 5 L | Technician stock and small equipment service | Use sealed packs and avoid carrying unidentified partial containers |
| 20 L | Workshop, contractor or multi-unit maintenance | Control batch traceability, dispensing equipment and moisture/contamination exposure |
| 200 L | Plant maintenance or distributor inventory | Define storage, turnover, sampling, traceability and clean transfer procedures before ordering |
Package size does not prove availability. Confirm current pack options, MOQ, lead time and labeling with the quotation. For hygroscopic synthetic oils, sealed handling is especially important; for mineral oils, clean and dry transfer still matters.
The request only says “mineral oil for R22” or “5GS for ammonia.” Ask for the compressor model, current oil and OEM grade. That short clarification can prevent an incompatible viscosity choice, an undocumented mixture or a warranty dispute.
No. 3GS may be a candidate in some R22 equipment, but the compressor specification and required viscosity control the decision. Check the factory oil and retrofit history before purchase.
Not from the grade name alone. The QISHANR reference values are 30 cSt, 55 cSt and 100 cSt at 40°C, so changing grades materially changes viscosity. Obtain OEM or engineering approval.
No. R717 systems differ by compressor design, temperature, oil separation and OEM requirements. Select the oil against the specific compressor manual and operating conditions.
It can be specified in selected equipment designed for those refrigerants, but compatibility and safe servicing must be confirmed for the exact compressor or appliance. Refrigerant-oil plausibility is not a conversion approval.
ISO VG32 is a viscosity classification around 32 mm²/s at 40°C. A product near that viscosity may enter the comparison, but buyers must also check the OEM specification, low-temperature behavior and complete TDS.
Do not mix them casually. Retrofit procedures may set residual-oil limits and require repeated oil changes or other steps. Follow the equipment, compressor and refrigerant conversion documentation.
At minimum, request the current TDS and SDS. Depending on the order, also request batch documentation, certificate requirements, packaging details, traceability and written cross-reference evidence.
Send Qishanr the compressor model, refrigerant, current oil, required viscosity, operating conditions, package size and destination. Our team can compare the request against available 3GS, 4GS and 5GS product data and identify which technical documents still need confirmation before quotation.
